Actron SCAN TOOL CP9110 User Manual

DOWN

RIGHT

LEFT

CP9110

Table of Contents

Vehicle Service Information ............. 2

Safety Precautions ............................ 3

Section 3:

Help and Troubleshooting

Tips ....................................19

3-1 Tool Problems ............................. 19

Section 1:

Welcome to The Scan Tool ..

3-2 Car Problems .............................. 20

1-1 Features ........................................ 4

1-2 The scan tool ................................. 5

1-3 What You Get ................................ 6

1-4 Cartridge and Installation .............. 6

1-5 Cables and Adapters..................... 7

3-3 Scan Tool Self-Tests ................... 20

• Display Test ........................... 21

• Keyboard Test ........................ 21

• Memory Test .......................... 21

Section 4:

How to Order

Accessories ......................22

4-1 Where to Buy?............................. 22

4-2 Call Actron Direct ........................ 23

4-3 E-Mail & Internet address ........... 23

1-6 Operating the scan tool ................. 9

• Powering-up the scan tool ....... 9

• Keyboard .................................. 9

• Display.................................... 10

• Lists, Menus, & Questions ..... 10

• Other Functions & Keys ......... 11

1-7 Scan Tool Setup .......................... 12

FULL ONE (1) YEAR WARRANTY

ActronManufacturingCompany, 15825Industrial

Parkway, Cleveland, Ohio 44135, warrants to the

user that this unit will be free from defects in

materials and workmanship for a period of two (2)

years from the date of original purchase.

Section 5:

Appendix ...........................24

Section 2:

Computer Vehicle Basics.. 13

Glossary of Terms ............................. 24

15825IndustrialParkway

Cleveland,Ohio44135

U.S.A.

Anyunitthatfailswithinthisperiodwillberepaired

or replaced at Actron’s option and without charge

whenreturnedtotheFactory. Actronrequeststhat

a copy of the original, dated sales receipt be

returned with the unit to determine if the warranty

period is still in effect.

2-1 Basics of Computer-

Controlled Cars ........................ 13

2-2 About Codes................................ 16

2-3 When to Read Codes .................. 17

Toll free U.S.: (800)228-7667

This warranty does not apply to damages caused

by accident, alterations, or improper or unreason-

able use.

ACTRON MANUFACTURING COMPANY DIS-

CLAIMS ANY LIABILITY FOR INCIDENTAL OR

CONSEQUENTIALDAMAGESFORBREACHOF

ANYWRITTENWARRANTYONTHEUNIT.

AllRightsReserved.

0002-002-2186

1-2 The Scan Tool

Section 1: Welcome to the Scan Tool – Basics

Actron’s scan tool was developed by ex-

perts in the automotive service industry to

help you diagnose today’s vehicles and

assist you in trouble-shooting procedures.

Computer-controlled vehicles have a net-

work of sensors that creates a series of

inputs to the engine computer. The com-

puter interprets these inputs and sends

outputs (commands) back to the network

to control air, fuel, vacuum, spark and

other critical functions. When a problem

occurs, the computer will store a record of

the event, and take corrective action to

adjust the circuit at fault. If the circuit does

not respond, or the problem cannot be

corrected, a trouble code is stored in the

computer’s memory. In some cases, the

Check Engine light may also be activated.

The scan tool will allow you to monitor

these vehicle events for trouble-shooting

and diagnosis, and to read codes from

the computer’s memory to pinpoint prob-

lem areas.

Lookup feature allows you to reference

code descriptions without having to page

through an instruction manual.

1-1 Actron Scan Tool Features

The Actron scan tool has

many features that you

would expect in scan tools

used by the professionals:

When the scan tool is connected to the

data connector, a communication link is

established, allowing the scan tool and

the vehicle’s on-board computer to ex-

change information. The way in which this

information is exchanged is referred to as

a data stream.

• Large 4 line x 20

character LCD display

• High-impact plastic case

• Durable, easy to use

keyboard

• Removable vehicle cable

adapter

As you use the scan tool, you will become

more proficient in trouble-shooting ve-

hicles using the detailed help messages

and code description information. Actron

will also help you become skilled in using

the scan tool for more than just “scanning”

the vehicle data list. We will show you

many other uses that will expand your

diagnostic limits by using the information

contained in the application manuals that

come with your Application Cartridge. No-

start, driveability, and emission problems

will be easier to diagnose than ever be-

fore.

• Removable power cable

Scan Tool & Application Cartridge

Vehicle Manufacturer Application Cartridges

The manufacturer-specific Application Cartridges offer a universal approach in chang-

ing software as vehicle technology changes. Actron’s separate cartridge and cable

system lets you add vehicle applications to meet your needs.

The scan tool uses state-of-the-art 16 “bit”

microprocessor technology and has twice

the computing power of some scan tools

costing thousands of dollars! The scan

tool is programmed to interpret the com-

puter signals and provide you with a “real

time” readout of vehicle data. More impor-

tantly, the software programs are written

to provide you with detailed, full-screen

readouts of all data. In addition, the Code

Cartridge Systems:

GM Cartridge

Ford Cartridge

Chrysler Cartridge

OBD II

1984-1995

1989-1995

1996-up

198

4-1

995

9-1

198

CHR

Optional Cable Adapters:

Chrysler CCD / LH – 6 Pin

Ford/Mazda MECS – 6 Pin

GM J1962-OBD-II – 16 Pin

Ford J1962-OBD-II – 16 Pin

Chrysler J1962-OBD-II – 16 Pin

Professional-Style Adapter Cables:

GM ALDL — 12 Pin

Ford EEC-IV/MCU — 7 Pin

Chrysler SCI — 6 Pin

tridge into the cartridge opening. Align the

cartridge slots with the “keyway” on the

main tool bottom opening. Continue to

gently push the cartridge into the opening

until you feel the main “edge connector”

resistance, then push to engage the car-

tridge to the cartridge stop. The cartridge

is engaged when the alignment of the

serial number tag is even with the top

edge of the Main Tool opening edge and

flush against the cartridge stop. Refer to

the example.

To remove the Application Cartridge simply

grasp the cartridge end and pull away from

the main tool. This action will disengage

the cartridge from the edge connector. Con-

tinue to pull the cartridge out of the open-

ing the rest of the way.

1-3 Actron CP9110 – What You Get

When you receive your scan tool, take time

MODEL NO.

SERIAL NO.

ACTRON MFG.

PATENT PENDING

to review all package contents.

CP9110

123456789

The Application Cartridge serial tag is

locatedonthetopcenterofthecartridge. This

serial tag will always be visible when the

cartridge is inserted in the main tool.

Actron Manufacturing warrants the software programs to

be accurate to the level of information released by the

Vehicle manufacturer at the time of release.

NOTE: You should always have the Ap-

plicationCartridgeinstalledbeforeyou

connect your unit to the power supply.

NEVER UNPLUG THE CARTRIDGE

WHEN POWER IS APPLIED!

(800) 228-7667

1-2325

Main Tool Model and Serial Tag

Please take time to review all important

documents enclosed. Be sure to review

both boxes for contents.

Review Box Contents

Main Tool Box

PATENT PENDING

CP9111

123456789

1984-1995 GM

In addition to the scan tool you should

have received the following items in the

main tool box:

• The Scan Tool

• Carrying Pouch

Cartridge Model and Serial Tag

1-5 Power Cables and Vehicle Adapters

Thescantoolcomeswithamainpowercable

designed to plug into the vehicle cigarette

lighter.Theotherendofthecableplugsintothe

scantoolasshownbelow.

Your scan tool has been designed to

operate at the same voltage levels as your

vehicle’s computer. It requires a minimum

of 8 volts to power-up. The scan tool is

circuit protected from voltage variations

and power surges. Should you have a

problem with power-up, review Section

3-1: Tool Problems to verify the nature of

yourproblem.NOTE:Somevehiclesshutoff

powertothecigarettelighterreceptaclewhen

theignitionkeyisintheOFForSTARTposi-

tions.Checkyourvehicletodeterminewhether

this is the case.

• Power Cable

• Main Tool Operator's manual

Before You Start

Take time to review the proper procedure

for powering-up your scan tool. The fol-

lowing section, Cartridge and Installation,

should be read before proceeding! This

will help you become familiar with all

operating procedures.

Application Cartridge Box

The Application Cartridge box that you pur-

chasedshouldcontainthefollowingitems:

• The Application Cartridge

• Vehicle Cable Adapter

• Application Manual for that vehicle

Connecting to Vehicle

Cigarette Lighter

1-4 Cartridge and Installation

Optional

Battery

Clip

Review the Application Cartridge instal-

lation procedure before you power-up

your scan tool. Hold the cartridge, serial

number tag up, and slowly insert the car-

Connecting to Scan Tool

DOWN

RIGHT

LEFT

DOWN

RIGHT

LEFT

Occasionally, you may find it necessary to

connect directly to the vehicle’s battery. In

these cases you may obtain an optional

battery clip adapter from Actron. Actron

also offers an AC power adapter to power

the scan tool with standard 110V wall

power. Both of these accessories may be

purchased directly from Actron.

MODEL NO.

SERIAL NO.

ACTRON MFG.

PATENT PENDING

1984-1995

DOWN

RIGHT

MODEL NO.

SERIAL NO.

ACTRON MFG.

PATENT PENDING

LEFT

AC 110V to 12V

Power Adapter

CP9110

12345678

1984-1995

1984-1995 GM

Application Cartridge Installed

Vehicle Cable Adapters

1-6 Operating the Scan Tool

Your scan tool Vehicle Ap-

plication Cartridge pack

Keyboard

Powering-up the scan tool

will contain the Applica-

tion Cartridge, application

manual and vehicle cable

adapter for one manufac-

turer (GM, Ford, or

Chrysler). The vehicle

cable adapter will be in-

stalled on the scan tool by

locating the large connec-

tor receptacle on the top

right side of the main tool.

Insertthevehiclecableinto

the scan tool receptacle and use the two

“thumb screws” to secure it to the connec-

tor as shown in the illustration below. Note

that you will feel a firm seating of the cable

as you secure it to the scan tool connector.

The vehicle cable adapter should always

be connected to the vehicle before power

is applied to the scan tool. This will enable

the scan tool to maintain a proper ground

between itself and the vehicle. If you have

connected to the vehicle, powered-up the

tool, and have difficulty establishing a link

between the scan tool and the vehicle,

check the following:

The scan tool software was designed for a

“userfriendly”approachinnavigatingthrough

operationalmenus.Thismakesthescantool

easytooperate.Simplyfollowtheinstructions

thatmatchthekeyboardsymbolsandyouwill

beusingyourscantoollikeanexpertinnotime.

Sincethekeyboardissealed,adampclothcan

be used to gently clean the surface. (Cau-

tion: DO NOT USE SOLVENTS LIKE

ALCOHOL! This could remove the

keyboard paint!)

The scan tool can be powered-up in three

ways. The most widely used way is with

the supplied cigarette lighter adapter. The

scan tool can also be powered up by using

the optional Battery Clip Adapter or 110/12V

AC Power Adapter. If you are powering-

up the scan tool for vehicle testing, then

make sure you connect the appropriate

cable to the data connector before you

supply power to the scan tool. If you do not

connect the vehicle data cable now, the

scantoolwillletyouknowthatyouhavenot

connected the data cable. If you just want

to power-up the scan tool to do self-tests,

then you do not need to attach the cable

to the data connector.

Connecting the

Vehicle Adapter Cable

When attaching the data cable to the ve-

hicle, take time to review the specific ap-

plication manual for the cartridge you are

using. This will instruct you on correctly

connecting the cable to the vehicle. Many

of the vehicle adapters are “keyed” so that

the adapter will fit only one way. If you find

that you have a special vehicle situation or

the adapter does not fit, call 1-800-

ACTRON-7forassistance. Alwaysdouble

check the application section to be sure

that you are following the proper hook-up

directions. Forfurtherhelpthatisnotavail-

able in the scan tool help screens, see

Section 3: Actron Help for solutions to

your scan tool problems.

Scan Tool Keyboard and Display

DOWN

RIGHT

LEFT

When the scan tool powers-up, a series of

screens is displayed. The screens start

with a “Welcome” screen and end with a

“Key Button Help” screen.

WelcomeTo

TheScanTool

ByActron

Keyboard Functions

The scan tool uses 8 keys to navigate

through the software-user interface:

PressHELPForKey

ButtonInformation.

1. Is the ignition on?

As you review the CP9110 Features sec-

tion on page 1-1 and 1-2, you will note

there is a complete view of accessory

vehicle adapter cables. They are for spe-

cial applications that only apply to certain

vehicles. If your vehicle is one of these,

you can order cables direct from Actron

by calling (800) 228-7667.

ENTER

Used to enter or answer a

2. Verify you have connected the vehicle

data cable to the vehicle’s Data Link

Connector (DLC).

software request.

PressENTERToCont

HELP

Used to request help when

the symbol is in the upper right hand

corner of the display.

3. Confirm that proper vehicle information

was entered into scan tool.

Welcome & Key Button Help Screens

The screens in between the “Welcome”

and the “Key Button Help” screen are for

a tool self-test and the cartridge software

version. Refer to this software version if

you need to contact Actron’s technical

support line with a problem. If you wish to

review the key button definitions, then

push the HELP key; otherwise, press

ENTER to continue forward.

FUNCTION Used to return user to

manufacturer’s function list.

BACKUP Used to move one screen

back in scan tool flow.

ARROWS UP or DOWN are always

used to move the solid cursor in the

direction of the arrow or scroll the data

list in the direction you want to move the

list

LEFT orRIGHTarrowsmove

the cursor in the direction of the arrow

and allow you to customize a vehicle

data parameter list.

Display

(NOTE: This is a GM Function List –

Function Lists for other manufacturers

may differ slightly.):

In these screens, brackets will automati-

cally be next to the default response. If you

wish to accept the default choice, simply

press ENTER. If you wish to change the

answer, use the LEFT or RIGHT arrow key

to move the brackets next to the other

response and press ENTER.

GMFunctionList

7)BeeperOn-Off

8)English-Metric

9)CodeLookup

The scan tool has a 4 line x 20 character

liquid crystal display (LCD) for easy view-

ing.Thismakesthescantool“userfriendly”

by offering a large viewing area to display

most Help and Instructional messages.

This also puts more information on the

display instead of referring you to printed

materials. Again the display will support a

number of helpful characters that will

prompt you through test routines. These

characters are shown below:

GMFunctionList

1)ReadCodes

2)Erase Codes

3)View Data

Notice now that there is only an arrow

pointing up in the last column. This indi-

catesthatyouhavereachedtheendofthis

list, and that all other choices are on

previous screens. You can return to those

screens by pressing the UP arrow key.

(NOTE: This is a GM Function List – Func-

tion Lists for other manufacturers may

differ slightly.).

Other Functions & Keys

Note how the cursor is pointing at 1) Read

Codes. If you wish to read trouble codes,

press ENTER to select that function. To

make a different choice, such as viewing

data, use the DOWN arrow key to move

the cursor down next to 3) View Data and

press ENTER. This will select the View

Data function.

As you have reviewed moving through

lists and functions in earlier sections, you

probably noticed several other symbols

on the screen. In the upper right-hand

Question Mark in upper right corner

means there is help available for this

screen.

corner of some screens, there is a large

These up and down arrow characters on

the screen are used throughout the scan

tool’s software. The UP and Down arrow

keys work exactly the same way, even if

you are just scrolling through text such as

the On-Line Help screen shown below:

This question mark indicates that On-Line

Help is available for that particular screen:

Bell in lower right corner means the

sound alert is on or active.

OperatingError.

CheckConnections!

TryAgain?

Sometimes, a list will be longer than three

or four items, and will not fit on a single

screen. In these cases, the down arrow

symbol ( ) is visible in the last column of

the display, indicating that there are more

choices on the next screen:

Cursor used to select menu choice.

Down Arrow indicates there is addi-

tional information on the next screen.

<Yes> No

3.TESTCONNECTOR:

DAMAGED/LOOSEPINS?

4.TOOLSETUPOK?

CORRECTVIN’S,ETC?

Up Arrow indicates there is additional

information on previous screen(s).

To enter On-Line Help, press the HELP

key. For the screen above, the help mes-

sage would look like this:

GMFunctionList

1)ReadCodes

2)Erase Codes

3)View Data

Below is a screen showing how these

symbols will look on your display (NOTE:

This is a GM Function List – Function Lists

forothermanufacturersmaydifferslightly.):

RECHECKFOLLOWING:

1.IGNITIONKEYON?

Note that there are no choices to make

here, and that there is no cursor to move.

There are, however, up and down arrows

in the last column. These arrows indicate

that there are other screens before and

after this one. Using the UP and DOWN

arrow keys, you can scroll through the

entire message.

2.HOOKUPTOVEHICLE

TESTCONNECTOROK?

GMFunctionList

4)Record Data

5)PlaybackData

6)Field Service

To go to the next choice, use the DOWN

arrow key to move the cursor down the list.

NOTE: Pressing the DOWN arrow key

moves the function list one line at a time.

After several DOWN arrow key presses,

the screen below appears.

All On-Line Help screens have their text

typed in ALL CAPITAL LETTERS. This is

another reminder that you are viewing On-

Line Help screens and not screens asso-

ciated with a function of the Function List.

Some On-Line Help messages are longer

than one screen. If this is the case, the

Occasionally, you may be asked a ques-

tion by the scan tool which requires a

response. These will always be YES or

NO questions, and are answered in al-

most the same way you make choices on

a Function List. Below is an example of a

YES/NO question:

Lists, Menus, and Questions

GMFunctionList

4)Record Data

5)PlaybackData

6) Field Service

The scan tool is designed to be as intuitive

as possible. That is, its functions and con-

trols should be easy to understand and

use the first time you try it. All scan tool

menus and screen lists operate the same

way. By using the UP and DOWN arrow

keys, you can move the cursor to a menu

selection of your choice. The ENTER key

selects that function. Below is an example

of a Function List with several choices

arrow symbols (

) will appear in the last

column of the display. A means there is

more On-Line Help information available

on the previous screen. Use the UP and

DOWN arrow keys to page up or down

through a series of On-Line Help screens.

Yes <No>

The On-Line Help screen shown above

hasa inthelastcolumn. Toviewthenext

On-Line Help screen, press the DOWN

arrow key. That screen is shown below:

1-7: ScanTool Setup

Section 2: Vehicle Computer Basics

Tool Setup is used to change the scan

tool’s default sound and measurement

unit settings. To change the scan tool’s

default settings, select the Tool Setup

option from the Function List (NOTE: This

is a GM Function List – Function Lists for

other manufacturers may differ slightly.):

2-1 Basics of Computer-Controlled Cars

3.TESTCONNECTOR:

DAMAGED/LOOSEPINS?

4.TOOLSETUPOK?

This section explains the engine com-

puter control system, the types of sensors

and how the computer controls engine

fuel delivery, idle speed and timing. Addi-

tional information may be found in techni-

cal support books at your local library or

autopartsstore.Themoreyouknowabout

the computer system, the better you can

diagnose vehicle computer problems.

gine. It is still an internal combustion en-

gine with pistons, spark plugs, valves, and

camshaft(s). The ignition, charging, start-

ing, and exhaust systems are very similar

as well. You test and repair these systems

just as before. The technical manuals for

these components show you how to per-

form the tests. Additionally, compression

gauges, vacuum pumps, dwell/tach

meters, engine analyzers, and timing

lights will continue to be used.

CORRECTVIN’S,ETC?

GMFunctionList

7)BeeperOn-Off

8)English-Metric

9)CodeLookup

Notice now that both arrow symbols (

)

are visible in the last column of the display.

This indicates that you can either page up

to a previous On-Line Help screen, or

page down to the next On-Line Help

screen by using the UP and DOWN arrow

keys. The previous On-Line Help screen

is always the one you just viewed, just as

with Function Lists.

After selecting the Tool Setup option, you

are given the choice to change either the

ScanTool’smeasurementunitsorwhether

Computer controls were originally in-

stalled on vehicles to meet federal gov-

ernment regulations for lower emissions

levels and improved fuel economy. This

began in the early 1980’s when basic

mechanical systems were no longer able

to accurately control key engine param-

eters. A computer could be programmed

to control the engine under various oper-

ating conditions, making the engine more

reliable. While these early systems were

very limited in the scope of their control,

providing only 10-14 trouble codes, they

did help guide the vehicle repair process.

the beeper will be On or Off. If the bell (

)

The Engine Computer Control system

symbol appears in the lower right hand

corner of the display, then the beeper is

turned On.

Another symbol on the screen you might

have noticed is the bell ( ) symbol in the

lower right-hand corner as shown below:

The vehicle’s on-board computer, or

Powertrain Control Module (PCM), is the

“heart” of the system. It is sealed in a metal

box and connected to the rest of the en-

gine by a main wiring harness. The PCM

is located, in most cases, in the passenger

compartment, behind the dashboard or in

the “kick panel” position, although some

manufacturers locate the computer con-

trol module in the engine compartment

area. Most PCMs can withstand a lot of

vibration and are built to live in a rugged

environment.

SetupToolFor

PressHELPForKey

ButtonInformation.

1)English/Metric

2)BeeperOn/Off

PressENTERToCont

Depending on whether you select English/

Metric or Beeper On/Off, the ScanTool will

display one of the following screens:

This bell symbol indicates that the sound

alert is on or active. Each time you press

akey,youshouldhearabeep.Ifyoudonot

see this symbol, then the keys should

remain silent when pressed. Information

on changing this setting is found in section

1-7: Scan Tool Setup.

Today, computercontrolshavemadecars

and trucks faster, cleaner, and more effi-

cient than ever before. In fact, without the

government mandates for fuel efficiency

and emissions control, cars and trucks

today would not be nearly as powerful,

reliable, and comfortable as they are.

MeasurementUnits

English(Default)

Metric

The PCM is permanently programmed by

the factory engineers. The program is a

complex list of look-up tables and instruc-

tions telling the computer how to control

the engine based on various driving con-

ditions. To do its job, the computer uses

sensors to know what is happening and

then provide instructions back to a net-

work of switches and actuators through-

out the vehicle.

BeeperSound

On(Default)

Off

What the computer controls:

The main control areas of the vehicle

computer are fuel delivery, idle speed,

spark advance, and emissions controls.

Some on-board computers may also con-

trol the transmission, brakes, and suspen-

sion systems as well.

When the beeper sound is turned Off, the

bell ( ) symbol will no longer appear on

the lower right hand corner of the display.

Sensors, switches, and actuators give

the computer information

NOTE: If you change the Beeper and

Measurement Units to a setting other than

the default, then all changes will revert

back to the default settings the next time

the scan tool is used.

What has not changed?

Sensors are devices which measure op-

erating conditions and translate them into

signals the computer can understand.

A computer-controlled engine is very simi-

lar to the older, non-computerized en-

sary—to give the O2 sensors time to warm

up to operating temperature.

Some examples of sensors: thermistors

(for temperature readings), potentiom-

eters (like a throttle position sensor), re-

lays (for voltage and signal readings), and

signal generators (such as an 02 sensor).

How the computer controls fuel deliv-

ery

position, manifold pressure (vacuum),

air flow and RPM.

As long as the engine and O2 and Coolant

TemperatureSensorsareatoperatingtem-

perature, the computer can operate in the

closed loop mode. Closed loop mode in-

sures that the air/fuel mixture is at the ideal

14.7:1 air/fuel ratio needed for efficient

combustion. But in stop and go cycles, the

O2 sensor may in fact cool down enough

that the computer will need to rely on a set

of internal parameters and go into open

loop mode again. In some cases, this may

also happen during extended periods of

idling. Many newer vehicles now use

heated O2 (HO2S) sensors to prevent this

condition.

Engine operation and emissions perfor-

mance depend upon precise fuel delivery

and ignition control. Early computer sys-

tems controlled fuel by electronically ad-

justing the carburetor metering and jet

systems. Soon, however, this was re-

placed by the more precise fuel delivery of

fuel injection.

• Air intake. Sensors used are: mass air

flow, manifold absolute pressure, mani-

fold air temperature and RPM.

The network of sensors has the job of

deliveringinformationthecomputerneeds

to know by converting it into electrical

signalsthecomputercanunderstand. Sig-

nals running from sensors to the PCM are

referred to as “inputs.”

• Air/fuel mixture status. Sensors used

are: oxygen sensor(s).

NOTE: Not all engines use every sensor

listed above.

In an electronically carbureted system,

the computer simply controls fuel flow

based on how far the throttle is opened by

the driver. The computer “knows” how

much air can flow through the carburetor

at various throttle openings, and adds the

appropriate amount of fuel to the mixture

at the carburetor.

Sensors monitor key things such as:

• Engine Temperature

Open and Closed Loop Modes:

Open or closed loop operation refers to

the way the computer is deciding how

much fuel to add to the air entering the

engine. During cold start and other low

demand, low temperature situations, the

computer operates in open loop mode.

This means that it is relying on a set of

internal calculations and data tables to

decide how much fuel to add to the incom-

ing air. It uses sensors such as the coolant

temperature sensor (CTS), the throttle

position sensor (TPS), and the manifold

absolute pressure sensor (MAP) to deter-

mine optimum mixtures. The important

difference here is that it does not check to

see if the mixtures are correct, leaving the

computer adjustment loop open.

• Intake Manifold Vacuum

• Throttle position

• RPM

• Incoming Air Temperature

• Volume of Incoming air

• Air Fuel Ratio, in percentage ( % )

In many vehicles, the computer controls

other systems related to open and closed

loop modes, including idle speed, elec-

tronic spark control, exhaust gas recircula-

tion, and transmission torque converter

clutches.Inopenloopmode,someofthese

systemswillbeadjustedtospeedthewarm-

ing of the engine and get the computer into

closed loop mode as quickly as possible.

Fuel injection is somewhat more sophis-

ticated in the way it delivers fuel. The

computerstilladdsanappropriateamount

of fuel to the entering air, but now it uses

fuel injectors (either in a throttle body or at

each intake port). Fuel injectors are far

more precise than carburetor jets, and

create a much finer fuel “mist” for better

combustion and increased efficiency. In

addition, most fuel injection systems have

ways of measuring exactly how much air

is entering the engine, and can calculate

the proper air/fuel ratio using lookup

tables. Computers no longer have to “es-

timate” how much air the engine is using.

INPUT

SENSORS

OBD II: The Next Horizon

ORS

In1994,manymanufacturersbeganequip-

ping cars with a new class of computer

technology which puts more processing

power under your dash than ever before. It

is called On-Board Diagnostics, Second

Generation, or OBD-II. It is required on all

vehicles sold in the US beginning January

1, 1996 (though most domestic manufac-

turers introduced it earlier than required),

and offers increased system monitoring

and diagnostic information. This new sys-

tem will store a library of 400 general

trouble codes and another 400 manufac-

turer-specific codes. These codes cover

Body Systems (B-Codes), Chassis Sys-

tems(C-Codes),andPowerTrainSystems

TUA

BRAINS OF THE

In closed loop mode, the computer still

decides how much fuel to add by using the

sensors listed above, and by looking up

the appropriate numbers on a data table.

However, it now checks itself to determine

whether the fuel mixture is correct. It is

able to check itself by using the informa-

tion provided by the oxygen sensor(s)

(O2S) in the exhaust manifold. The oxy-

gen sensors will tell the computer if the

engine is running rich or lean, and the

computer can take steps to correct the

situation. Inthisway, thecomputer closes

the adjustment loop by checking itself and

making necessary corrections. It should

be noted that the O2 sensors must be at a

very high operating temperature (approxi-

mately 650° F) before they will begin to

feed information back to the computer.

This is why open loop mode is neces-

COMPUTER

In many modern systems, the computer

also uses information provided by sen-

sors to give it an idea of how well it is doing

itsjob, andhowtodoitbetter. Sensorscan

tell the computer how warm the engine is,

how rich or lean the fuel mixture is, and

whether accessories (like the air condi-

tioner) are running. This feedback infor-

mation allows the computer to “fine tune”

the air/fuel mixture, keeping the engine

operating at its peak.

Switches and Actuators are electric de-

vices energized by the computer to allow

commands to perform a specific function.

Switches are often called relays (such as

the coolant fan switch). Actuators might

include solenoids (such as fuel injector

valves) and small motors (such as the Idle

Speed Control). Not all of the computer’s

outgoing signals are routed to switches

and actuators. Sometimes information is

sent to other system computers like trans-

mission, brakes, ignition modules, and trip

computers. Signals running from the PCM

to other components are called “outputs.”

What the Computer needs to know:

• Engine operating condition. Sensors

used are: coolant temperature, throttle

(P-Codes). Now, basic terms are standard-

ized and all generic codes will share a

common format and terminology that the

manufacturers and the Society of Auto-

motive Engineers (SAE) designed. You

will be glad to know that as your car gets

smarter, it will be easier for you to keep

track of what is going on under the hood.

servicing a particular trouble code take

into account all the possibilities. If you

follow these procedures, you should be

able to find the problem causing the code

and fix it yourself.

Trouble Codes and Diagnostics help

you fix the problem

To find the cause of the problem yourself,

you need to perform special test proce-

dures called “diagnostics.” These proce-

dures are in the vehicle service manual,

and your scan tool makes it easy to locate

and diagnose malfunctioning systems.

There are many possible causes for any

problem. For example, suppose you

turned on a wall switch in your home and

the ceiling light did not turn on. Is it a bad

bulb or light socket? Are there problems

with the wiring or wall switch? Maybe

there is no power coming into the house!

As you can see, there are many possible

causes. The diagnostics are written for

Actron makes it easy to fix computer-

controlled vehicles

Using the Actron scan tool to obtain

trouble codes is fast and easy. Trouble

codes give you valuable knowledge -

whether you go for professional service or

do it yourself. Now that you know what

trouble codes are and where they come

from, you are well on your way to fixing

today’s computer-controlled vehicles!

2-2 About Codes

Where do Trouble Codes come from and what are they for?

Engine computers can find problems

Code numbers reveal test results

The computer systems in today’s vehicles

do more than control engine operations—

they can help you find problems, too! Spe-

cial testing abilities are permanently pro-

grammed into the computer by factory

engineers. These tests check the compo-

nents connected to the computer which

are used for (typically): fuel delivery, idle

speed control, spark timing, emission sys-

tems, and transmission shifting. Mechan-

ics have used these tests for years. Now

you can do the same thing by using your

Actron scan tool!

The test results are stored by using code

numbers, usually called “trouble codes”

or“diagnosticcodes.”Forexample,acode

22 might mean “throttle position sensor

signal voltage is too low.” Code meanings

are a part of your scan tool’s software—all

you have to do is look them up! But since

code definitions vary with manufacturer,

model year, and engine, you may also

want to refer to a vehicle service manual

for additional information. These manu-

als are available from the manufacturer,

other publishers, or your local public li-

brary. See page 2 for more information on

ordering service manuals.

2-3 When to Read Codes

Many vehicles have a “Malfunction Indicator Lamp” or MIL, which has been referred to

as a “Check Engine” light in the past. With the advent of OBD-II, all engine trouble lights

are now called “Malfunction Indicator Lamps” or MIL.

UsetheMalfunctionIndicatorLamptotellyouwhentroublecodeshavebeen

stored in memory:

About the Malfunction Indicator Lamp

Enginecomputersperformspecialtests

• “Check Engine”

The engine computer runs the special

tests, depending on the manufacturer,

engine, model year, etc. There is no “uni-

versal”testthatisthesameforallvehicles.

The tests examine INPUTS (electrical sig-

nals going INTO the computer) and OUT-

PUTS (electrical signals coming OUT of

the computer), as well as internal calcula-

tions made by the computer. Input signals

which have “incorrect” values, or output

circuits which do not operate properly are

noted by the test program and the results

are stored in the computer’s memory.

These tests are important. The computer

cannot control the engine properly if it has

incorrect input information or faulty output

circuits.

• “Service Engine Soon”

• “Service Engine Now”

Read Trouble Codes with the scan tool

You can obtain trouble codes from the

engine computer memory by using the

scan tool. You can also monitor the opera-

tion of systems throughout the vehicle,

helpingtopinpointthesystemwherethere

may be a problem. Once you have read

the trouble codes, you can either:

• marked with a small engine picture or

diagram

The Malfunction Indicator Lamp is nor-

mally OFF when the engine is RUNNING.

MalfunctionIndicatorLamp:

normal operation

NOTE: The Malfunction Indicator Lamp

will turn on when the ignition key is in ON

position, but the engine is OFF prior to

starting the vehicle. This is a normal test of

all the dashboard message lights.

• Have your vehicle professionally ser-

viced.

The engine computer turns the Malfunction

Indicator Lamp on and off as needed. This

dashboard message is either amber or

red and labeled:

Or,

• Repair the vehicle yourself using the

trouble codes to locate the source of the

problem.

MalfunctionIndicatorLamp:

problem spotted

Poorly running engine, no Malfunction

Indicator Lamp

Section 3: Actron Help

If the Malfunction Indicator Lamp does not

come on, you may have an electrical prob-

lem which needs repair. Refer to the “Di-

agnostic Circuit Check” steps in the “Basic

Diagnostic Procedures” section of your

vehicle service manual.

Most likely, this condition is not due to

computer system failures, but reading

codes can still be useful as part of a basic

trouble-shooting procedure. Check wir-

ing and bulb for “Check Engine” light

failures. Refer to vehicle service manual

for additional diagnostic information.

3-1 Tool Problems

There may be times when your scan tool

does not seem to be communicating with

the vehicle. It is possible that the vehicle’s

computer will stop communicating, but for

the most part, if you loose the “link,” you

should check the vehicle power adapter

and the cigarette lighter circuit first. Since

the scan tool has built-in diagnostics, it is

easytoisolateaproblemwiththeScanTool

itself. There will be two basic types of

problems that you will deal with: vehicle

problems and tool problems. Both might

affect your test. Remember, the scan tool

always goes through a SELF CHECK

each time you power the unit up, before

testing. Use the trouble-shooting tips be-

low to help diagnose scan tool problems

before calling Actron’s Technical Support

line:

thevehiclecigarettelighterreceptacle.

2. Toolwillnot“Link”tothevehiclecom-

puter:

A. Unplug the vehicle Data Link Connec-

tor (DLC) adapter and plug it back in to

verify that it is properly plugged into the

vehicle DLC.

MalfunctionIndicatorLamp:

intermittent problem

IMPORTANT: Some vehicles may not be

equipped with Malfunction Indicator

Lamps.Somemid-80’sFords,forexample,

did not use a Malfunction Indicator Lamp

to warn of problems. On vehicles without

Malfunction Indicator Lamps, it is more

difficult to recognize problems. Some

symptoms of a computer- or sensor-

related problem might be:

When the light remains ON after the en-

gine is RUNNING:

B. Review the vehicle VIN information and

verify that you have properly entered

the correct vehicle VIN information in

the scan tool setup. Also review the

Actron supported vehicle list (found in

scan tool Application Cartridge

manual).

• The computer sees a problem that does

not go away (known as a “current” fail-

ure).

• The light will stay on as long as the

problem is present.

• A trouble code is stored in computer

memory (a “history” or “memory” code).

C.In some GM cars, if there is a Trouble

Code set that refers to the internal

MEMCAL-PROM, you may not get a

vehicle data stream.

• Hard starting

• Poor idle quality

• Use the scan tool at the earliest conve-

nient time to obtain codes.

• Poor fuel mileage

• Misfiring or hesitation

• Black or dark gray smoke from tailpipe

• Failure of emissions tests

When the light comes ON, then goes OFF

while the engine is running:

1. The scan tool will not power-up:

3. Your scan tool will not record data:

• The computer saw a problem, but the

problem went away (known as an “in-

termittent” failure).

A. Check the cartridge – Is it properly

seated?

A. Take time to review the vehicle applica-

tion manual for the vehicle that you are

working on. Refer to the data recording

section, following the instructions and

try again.

In vehicles without a Malfunction Indicator

Lamp, it is important to be alert to any

warningsignsofcomputersystemtrouble.

This is why the scan tool is so valuable.

With it, you can diagnose any vehicle’s

electronic systems, regardless of whether

the vehicle is equipped with a Malfunction

Indicator Lamp. It is also important to note

that vehicles without Malfunction Indica-

tor Lamps DO store trouble codes just like

any other computer-controlled vehicle.

Reading codes is still a very important part

of diagnosing problems on these vehicles.

B. Check the cigarette lighter for power.

Take the cigarette lighter element and

plug it in to verify that it is heating up. If

not, check lighter fuse.

• A trouble code is stored in computer

memory (a “history” or “memory” code).

• The light went out because the problem

went away, but the code stays in

memory.

B. Verify that the scan tool memory buffer

is not already full.

C.UN-plug and plug back in to verify the

cigarettelighterendisproperlyseatingin

C.Use the scan tool self-test and verify

that the on-board RAM memory is okay.

• Use the scan tool at the earliest conve-

nient time to obtain codes.

NOTE: The computer will automatically

erase these codes after several restarts if

the problem does not return.

4. YourKeyboarddoesnotfunctionprop-

erly:

NOTE:OnvehiclesequippedwithOBD-II,

the Malfunction Indicator Lamp also sig-

nals an emissions-control related failure.

The vehicle may not run any differently,

but the OBD-II system is designed to note

very small changes in the engine’s opera-

tion which could lead to emissions dam-

age or failure.

A. Perform the Keyboard Test by entering

the Self-Test and select the Keyboard

Test function. This will test out all but-

tons along with the sound alert.

B. If the keyboard test shows nothing

and you still experience the problem,

thencallActron’s technical supportper-

sonnel at 1-800-ACTRON-7.

The screen below is how the Tool Self-

Tests option appears on the Function List

(NOTE: This is a GM Function List. Func-

tion Lists for other manufacturers may

differ slightly):

done. If you selected Tool Self-Test from

the Function List, then press the FUNC-

TIONkeytoreturntothefunctionlistatany

time.

3-2 Car Problems

tion PROM matches the vehicle setup.

Some GM vehicles have had replace-

ment PROMs installed from newer ve-

hicles to correct driveability problems.

Check the scan tool Application Car-

tridge manual for applicable models

and years.

If your scan tool is having difficulty “link-

ing” with the vehicle computer, be sure

that you have double checked all scan

tool interfaces, including the power con-

nectors and the DLC connection. When

you are sure that the scan tool is not

malfunctioning (run scan tool Self-Tests),

then the problem may be with the vehicle’s

electrical system or with the vehicle com-

puter itself. Check the following:

GMFunctionList

7)Tool Setup

8)ToolSelf-Test

9)CodeLookup

• Make sure the vehicle’s on-board com-

puter has a good ground. If your

vehicle’s on-board computer has a

ground going directly to the computer’s

case, then clean up this connection

and apply a conductive grease to the

mating surfaces.

NOTE: The beeper is disabled while the

Display Test Screen is visible. Therefore

any key press will not register a beep.

ToselectToolSelf-Testsoneitherscreen,

use the UP and DOWN arrow keys to

move the cursor so it is pointing to the Tool

Self-Tests option, then push the ENTER

key to select this option.

• If you are using the cigarette lighter

power adapter, verify that the vehicle’s

cigarette lighter and fuse are OK.

Keyboard Test

The Keyboard Test is used to check the

functionality of the scan tool’s keyboard.

After you select Keyboard Test from the

Tool Self-Test Menu, the Keyboard Test

screen with instructions is displayed.

• If the cigarette lighter adapter is used to

power-up the scan tool, then make sure

the vehicle’s battery has a minimum 8

volt charge. The scan tool requires a

minimum of 8 volts to power-up.

After selecting the Tool Self-Tests option,

you will be given a menu of scan tool self-

tests to choose from:

• On some carbureted engines, the igni-

tion key must be ON and the engine

OFF in order to establish communica-

tion between the scan tool and the

vehicle’s on-board computer. If the en-

gine was running when the Operating

Error occurred, then turn the ignition

key OFF and then ON, but do not start

the engine.

Tool Self-Test

1)DisplayTest

2)KeyboardTest

3)Memory Test

PushButtonToTest

KeyAndDisplay

NameKey:

• Verify the ignition key is ON and not in

the accessories (ACC.) position.

BACKUPWhenDone.

• Check the vehicle’s on-board computer

for a blown PCM fuse. The PCM fuse is

located on the fuse block in the passen-

ger compartment. If the PCM fuse is

blown, the vehicle’s on-board computer

cannot transmit data.

From the above menu, use the UP and

DOWN arrow keys to move the cursor so

it is pointing to the Self-Test option of your

choice, thenpushtheENTERkeytoselect

this option.

Eachtimeyoupressakey,checkscantool

display. The key name should appear and

the scan tool should beep. For example,

if you press the UP arrow, the screen will

display “Key: UP ARROW.” If the button

name is not displayed, the key is not

working.TheonlyexceptionistheBACKUP

key. When the BACKUP key is pressed,

the scan tool returns to the Tool Self-Test

Menu. If you are not returned to the Tool

Self-Test Menu, then the BACKUP key is

not working. NOTE: The FUNCTION key

will not return you to the Function List

while you are keyboard testing.

• As a last resort, the vehicle’s on-board

computer or calibration PROM may be

defective.Checkvehicleservicemanual

to determine correct computer tests for

your particular vehicle.

• Check to be sure your vehicle’s calibra-

Display Test

After you have selected Display Test as

your choice, a screen detailing the test is

displayed. The Display Test will fill every

pixel of the ScanTool’s LCD display with

a solid black character. Press ENTER to

display solid black characters.

3-3 Scan Tool Self-Tests

sible during scan tool power-up. If a key-

board problem happens while you are

Viewing Data, it is easier to run a Key-

board Self-Test from the Function List

than to remove and then re-apply power

to the scan tool.

Scan tool Self-Tests are used to test the

operation of the scan tool’s display, key-

board, and internal memory. The Tool

Self-Tests menu can be accessed when

the scan tool is initially powered-up, and

from the Function List. Convenience is the

reason the Tool Self-Tests menu is acces-

sible in two ways. If the scan tool has a

display problem on power-up, you do not

want to enter vehicle set-up information

just to get to the Function List to run the

Display Self-Test. It is far more convenient

to have the Tool Self-Tests menu acces-

ENTERToTest.Look

ForMissingSpots

InDisplay.Press

Memory Test

The scan tool has already run a Memory

Self-Test during power-up. It is assumed

thatthescantoolpassedtheMemorySelf-

Test on power-up, because you should

not have proceeded any farther if it failed.

Once you have reached the Function List,

the scan tool may have trouble playing

After the ENTER key is pressed, the dis-

play on power-up looks like this:

BACKUPWhenDone

The Display Test Screen is shown below.

Look for pixels that are not black. In other

words, look for missing spots in the solid

black characters. Press the BACKUP key

to return to the Tool Self Test Menu when

SelectFunction

1)NewVehicle

2)ToolSelf-Test

back recorded data, displaying trouble

code definitions, or doing any other func-

tion that uses the scan tool’s internal

memory. If this happens, it is a good idea

to run the Memory Test again. From the

Tool Self-Test Menu, select the Memory

Test option. A “working please wait” mes-

sage is displayed while the scan tool tests

its internal memory:

played. Press the ENTER key to return to

the Tool Self-Test Menu.

4-2 Call Actron

4-3 E- Mail &

Internet Address

Actron is also available electronically for

comments and ordering information.

Actron’s E-Mail address is:

In addition to your local dealer, all Actron

equipment and replacement parts are

available directly from the Actron factory.

Product catalogs, pricing information, and

replacement components can be ordered

by contacting Actron directly.

MemoryTestFailed

PressENTERToCont

MemoryTestPassed

PressENTERToCont

[email protected]

And while you’re on-line, be sure to check

out Actron’s Website, where you’ll find

equipmentinformation, newproducts, and

technical tips to help you make the most of

your new Actron ScanTool.

By US mail:

Actron Manufacturing Company

15825 Industrial Parkway

Cleveland, OH 44135, USA

Working

**PleaseWait**

By phone:

1-800-228-7667

On the World Wide Web:

NOTE: If you selected Tool Self-Test from

theFunctionList,thenpresstheFUNCTION

key to return to the function list at any time.

When the Memory Test is completed,

either a “Memory Test Failed!” or a

“Memory Test Passed!” message is dis-

http://www.actron.com

By fax:

(216) 651-2388

For Technical Support call:

1-800-ACTRON-7

Section 4: Accessories and How to Order

4-1 Where to Buy

Actron offers a complete line of high qual-

ity automotive diagnostic and repair

equipment. Additional cartridges, cables,

connectors, and adapters for the scan

tool are available from the local retail

store where you originally purchased

your scan tool. The table below lists the

scan tool accessories.

Actron

Kits:

Model Number Replacement Parts:

Part Number

GM OBD II cable kit

CP9115

CP9116

CP9120

CP9117

CP9118

CP9119

Cigarette power cable

Carrying Case

Main Tool operators manual

GM cartridge manual

Ford cartridge manual

Chrysler cartridge manual

38-1908

400-2080

2-218601

2-218301

2-218401

2-218501

Ford Probe MECS cable kit

Chrysler L-H engine cable kit

Chrysler OBD II cable kit

Battery Clip Adapters

AC power converter 110/12V

vehicles. This information is used to design and

build aftermarket diagnostic equipment.

then the duty cycle is 25%. A duty cycle of 0%

means the signal is always at a “low” value and

not changing. A duty cycle of 100% means the

signal is always at a “high” value and not chang-

ing. The PCM uses duty cycle type signals when

it wants more than just “on-off” control of an

actuator. This is how it works: A 50% duty cycle

signal going to a vacuum switching solenoid

means the solenoid will be “on” (passing full

vacuum) half the time, and “off” (passing no

vacuum) half the time. The average amount of

vacuum passing through the solenoid will be one

half the full value because the solenoid is only

“on” for half the time. This signal changes at a

rapid rate, as often as ten times per second. Thus

the PCM can get a vacuum controlled actuator to

move halfway between “no vacuum” and “full

vacuum.” Other positions can be achieved by

changing the duty cycle of the control signal

which in turn changes the average amount of

control vacuum.

Section 5: Glossary of Terms

Detonation: Uncontrolled ignition of the air/fuel

mixtureinthecylinder.Alsoreferredtoas“knock,”

detonation indicates extreme cylinder pressures

or “hotspots” which are causing the air/fuel mix-

ture to detonate early. High cylinder pressures

may be caused by excessive load (trailer towing,

A/C operation, etc.) or by too much spark ad-

vance. High octane fuel has a higher resistance

to uncontrolled ignition, and may be used to

control detonation when the PCM is unable to

retard timing sufficiently to prevent it from occur-

ring. NOTE: High octane fuel is not a cure for the

problem, only the symptom. If your vehicle expe-

riences long-term detonation, check for other

causes.

Actuator: Devices that are powered by the PCM

ClosedLoop(C/L):Thisiswhenacontrolsystem

performs an action (expecting a certain result),

then checks the results and corrects its actions

(ifnecessary)untilthedesiredresultsareachieved.

Example: Fuel delivery. The PCM operates a fuel

injector in a way that should deliver an optimum

air/fuel mixture, as long as everything in the fuel

system is operating as expected. In closed loop

operation, the PCM uses the oxygen sensor to

check the results (fuel delivery may be different

than expected because of variations in fuel

pressure or injector operation). If the oxygen

sensor indicates a “rich” condition, the PCM will

compensate by reducing fuel delivery until the

oxygen sensor signals an optimum air/fuel mix-

ture. Likewise, the PCM will compensate for a

“lean” condition by adding fuel until the oxygen

sensor once again signals an optimum air/fuel

mixture.

to control things. Actuator types include relays,

solenoids, and motors. Actuators allow the PCM

to control engine operation.

A/F: Air/Fuel ratio. This refers to the proportion of

air and fuel delivered to the cylinder for combus-

tion. For example, if you have 14 times more air

than fuel (by weight) then the A/F ratio is 14:1

(read as “fourteen to one”). The ideal operating

A/F ratio in an automotive application is 14.7:1.

Check Engine Light (CEL): The “Check Engine”

light (CEL) will illuminate when the PCM detects

a circuit malfunction in any of the engine feed-

back circuits. When the malfunction occurs, the

CEL will remain lit as long as the PCM detects the

circuit problem. This will automatically set and

store a trouble code in the PCM’s memory. Some

manufacturersalsorefertotheCELasaMalfunc-

tion Indicator Light (MIL), or the Emissions Main-

tenance Lamp (EMR) on some Chrysler trucks.

Diagnostic Trouble Codes: Diagnostic Trouble

Codes (DTC) indicate a malfunction flagged by

the PCM. The PCM will display a corresponding

numerical code number based on a look-up table

in the program of the on-board computer. De-

pending on the manufacturer, the number of

DTCs vary by vehicle and supported systems.

Most systems have the ability to store codes in

memory, which are commonly referred to as

“history codes” or “soft codes.” Malfunctioning

circuits will generate continuous Check Engine

lamp illumination, called “current codes” or “hard

codes.” History codes, based on the

manufacturer’sdiagnosticstrategy,willbecleared

from the PCM’s memory after several ignition

circuitstartcyclesifthecircuitdoesnotreflectthe

failure again. This capability does allow the

technician to access some information on which

circuits were malfunctioning at a previous point.

OBD-II systems will transmit many more DTCs

than the past systems, and therefore will allow a

technician the ability to better pin-point failures

and past events. They only way to clear codes on

OBD-II systems will be with a scan tool that has

the proper programming to perform the function.

DVM: Digital Volt Meter. An instrument using a

numeric readout to display measured voltage

values as opposed to a moving needle on a

gauge face. Usually the instrument has other

measuring capabilities, such as resistance and

current, and may be called a Digital Multi-Meter

(DMM). Most DVMs have 10 Megaohm input

impedance. This means the circuit under test will

not be electronically disturbed when the DVM is

connected for a measurement.

Thus, closed loop operation means the PCM can

“fine tune” control of a system to achieve an exact

result providing the PCM has a means to check

results (like an oxygen sensor).

C3 or CCC: Computer Command Control. The

name of the General Motors electronic engine

control system used on most vehicles built since

1982.,

Data Link Connector (DLC): The Data Link

Connector (DLC) is a universal term for the

interface port between the vehicle’s on-board

computer and the ScanTool. It is sometimes

referred to as the Assembly Line Diagnostic Link

(ALDL), Vehicle Interface Port (VIP), or Serial

Communication Interface (SCI). The DLC is able

to transmit PCM data to the ScanTool as it is

processed. The DLC may be located in the

engine compartment or in the passenger com-

partment, depending on manufacturer. DLC de-

sign also varies from manufacturer to manufac-

turer, ranging from a 6-pin to a 17-pin connector

interface. All vehicles with OBD-II use a 16-pin

connector located in the passenger compart-

ment. The ScanTool requires manufacturer-spe-

cificadaptercablestolinkwithnon-OBD-IIDLCs.

ChryslerSerialCommunicationInterface(SCI):

This is Chrysler’s vehicle adapter (or Data Link

Connector) used to link scan tools with the PCM.

EarlyChryslerOBDsystems(1981-83)broadcast

trouble codes, but gave no operating parameter

data. In 1983, the second phase of Chrysler

OBD, called the Serial Communication Interface

(SCI), was introduced with expanded serial data

and many test modes for the technician to access

with a scan tool. SCI provides the following

modes to access vehicle data: Diagnostic Test

Mode, CircuitActuationTestMode(ATM), Switch

Test Mode, Sensor Test Mode, and Engine

Running Test Mode. Each of these modes allow

for different procedures of diagnostic tests and

test routines. These routines are programmed

into the Chrysler Logic Module (LM) which then

passes the information on to the power module

or Single Board Engine Controller (SBEC). The

vehicle diagnostic adapter is located in the en-

gine compartment on the right-hand side, next to

the SBEC unit with a dust cap marked “Diagnos-

tic.”

ECM: Electronic Control Module. The “brains” of

the engine control system. It is a computer

housed in a metal box with a number of sensors

and actuators connected with a wiring harness.

Its job is to control fuel delivery, idle speed, spark

advancetiming, andemissionsystems. ThePCM

receives information from sensors, then ener-

gizesvariousactuatorstocontroltheengine. The

ECM is frequently called the PCM (Powertrain

ControlModule)invehicleshavingothercomputers.

These other computers are used for climate

control, entertainment systems, transmissions,

etc.

DIS: Distributorless Ignition System or Direct

Ignition System. A system that produces the

ignition spark without the use of a distributor.

Data Stream:Thisistheactualdatacommunica-

tions broadcast from the vehicle’s PCM to the

diagnostic connector. The individual manufac-

turers determine the number of “data bytes” a

specific engine will broadcast. The size of the

data stream is usually dependent on the com-

plexity of the engine, transmission, ABS, and

other systems supported by the PCM. All manu-

facturers supply program documents for each

year, engine, and option combination that a

particular PCM supports in all the manufacturer’s

EFI: Electronic Fuel Injection. A term applied to

any system where a computer controls fuel deliv-

ery to the engine by using fuel injectors.

Duty Cycle: A term applied to frequency signals

— those which are constantly switching between

a small voltage value (close to zero) and a larger

value (usually 5 volts or more). Duty cycle is the

percentage of time the signal has a large voltage

value. For example, if the signal is “high” (large

voltage) half of the time, the duty cycle is 50%.

If the signal is “high” only one fourth of the time,

Engine Parameters: This is the translated infor-

mation that is displayed on the scan tool screen.

Parameters will include the information inputs

and the output signals from the PCM.

ESC: Electronic Spark Control. This is an ignition

system function that works on vehicles having a

knock sensor mounted on the engine block. The

knock sensor is wired to circuitry in a separate

module (early version) or inside the PCM (later

versions). If the sensor detects engine knock, the

ESC function alerts the PCM which will immedi-

ately retard the spark to eliminate the knocking

condition.

Functional Tests: These are tests of PCM-

controlled systems, such as the fuel pump, the

“Check Engine” light, and other switches and

actuators. Functional Tests are generally depen-

dent on the vehicle manufacturer’s OBD strategy

and the PCM diagnostic architecture. Functional

tests require that the scan tool have the ability to

perform bi-directional communications with the

vehicle’s PCM. This means that the scan tool

must “talk” to the vehicle’s PCM, instead of just

“listening” to the incoming vehicle data stream.

Examples of functional tests are: Chrysler’s ac-

tuator/switch tests that allow you to review the

operation of a switch as you turn it on or off from

the driver’s seat, and turning the fuel pump on

and off. On a GM vehicle, a functional test is

placing the vehicle in Ground Mode to check the

PCM’s self-test diagnostics and the “Check En-

gine” lamp operation.

makes the element sensitive only to engine

vibrations associated with detonation (“knock-

ing”).

On-Board Diagnostics, Phase II (OBD-II): With

the passing of the 1990 Clean Air Act Amend-

ment, the EPA imposed more stringent require-

ments which include the addition of multiple

oxygen sensors, one before the catalytic con-

verter and one after to provide the PCM with

information on catalyst efficiency and condition.

There are also computer-controlled EGR, fuel

pressure regulators, and smart ignition systems.

Inaddition, OBD-IIrequiresacommondiagnostic

connector and location, as well as an industry-

standard data message, both defined by an

industry committee made up of engineers from

most major manufacturers and the SAE. Vehicle

manufacturers are required by law to provide at

least a minimum amount of data for emissions

programs to access the critical emissions data

available through OBD-II. OBD-II began to ap-

pear in vehicles in late 1994, and is required

equipment on all cars sold in the US after January

1, 1996.

MFI: Multi-Port Fuel Injection. See “MPFI” defini-

tion.

MIL: Malfunction Indicator Lamp. Also known as

a Check Engine Light or CEL.

Mode:Atypeofoperatingcondition, suchas“idle

mode” or “cruise mode.”

EST:ElectronicSparkTiming. Anignitionsystem

where the PCM controls the spark advance

timing. A signal called EST goes from the PCM to

the ignition module which fires the spark coil. The

PCM determines optimum spark timing from sen-

sor information – engine speed, throttle position,

coolant temperature, engine load, vehicle speed,

Park/Neutral switch position, and knock sensor

condition.

MPFI: Multi-Port Fuel Injection. A fuel injection

system using one (or more) injector(s) for each

cylinder. The injectors are mounted in the intake

manifold, and fired in groups rather than individu-

ally.

M/T: Manual transmission or manual transaxle.

NOx: Oxides of Nitrogen. A pollutant. The EGR

system injects exhaust gases into the intake

manifold to reduce these gases at the tailpipe.

FBC: Feedback Carburetor. This is used on early

versions of computer-controlled engines. It is a

carburetor which can have its fuel delivery modi-

fied by an electronic signal from the PCM. The

signal controls a mixture control solenoid (MCS)

attached to the carburetor body.

Ground: The return path for current to flow back

to its source (Usually the negative battery termi-

nal). It is also the reference point from which

voltage measurements are made (the connec-

tion place for the negative (-) test lead from a

voltmeter).

Open (Circuit): A break in the continuity of a

circuit such that no current may flow through it.

On-BoardDiagnostics(OBD):Asvehiclemanu-

facturers developed on-board diagnostics for

their service procedures and to meet EPA regu-

lations, the first phase of this computerization

was referred to as OBD. This technology started

in the late 1970’s and carried through to the early

1980’s. Most of these early systems were very

crude, especially when compared to today’s

OBD. Manyrequiredamanufacturer-specifictool

to read trouble codes and other computer infor-

mation. This technology used a feedback loop

system to monitor exhaust emissions and pro-

vided computer control of the vehicle’s fuel

system.

OpenLoop(O/L):Thisiswhenthecontrolsystem

performs an action (expecting a certain result),

but has no way of verifying if the desired results

were achieved. Example: The PCM operates a

fuel injector expecting a certain amount of fuel to

bedelivered(ThePCMassumeseverythinginthe

fuel system is performing properly). In open loop

operation, the PCM has no way of checking the

actual amount of fuel delivered. Thus, a faulty

fuel injector or incorrect fuel pressure can change

the amount of fuel delivered and the PCM would

not know it.

Ford Electronic Engine Control IV (EEC-IV):

This is the name of Ford’s Powertrain Control

Module (PCM) used in all Ford cars and trucks

since the mid-1980’s. It is designed to be read by

aftermarket scan tools. Earlier versions of this

PCM were referred to as EEC-I, EEC-II, or EEC-

III, and were only accessible by the dealer via a

specific diagnostic tool. On carbureted vehicles,

Ford used a system called the Microprocessor

ControlledUnit(MCU),whichisaccessiblethrough

an adapter similar to the EEC-IV’s. Other varia-

tions of the EEC-IV vehicle adapter are used on

Ford’shybridvehicles,suchastheProbeandsome

Escort/Tracer models, which use Mazda PCMs

and have different protocols and codes. Informa-

tion on these vehicles is widely available, and

most scan tools support these vehicles as well as

the standard Ford EEC-IV systems. Ford’s diag-

nostic strategy offers several avenues to access

codes and test procedures.

Inputs: Electrical signals running into the PCM.

These signals come from sensors, switches or

other electronic modules. They give the PCM

information about vehicle operation.

KOEO: Key On, Engine Off. A test mode where

the PCM is active and feeding data parameters,

but the engine is not running. Because the

engine is not running, some data parameters

may not be accurate or available in this mode. On

Ford vehicles, KOEO testing is the only way to

read memory codes stored in the PCM.

On-Board Diagnostics, Phase I (OBD-I): By

1985, theCaliforniaAirResourcesBoard(CARB)

had called for more uniform diagnostic systems

to be used on vehicles sold in California. Com-

bined with federal exhaust emission regulations

enacted in the early 1990’s, CARB required that

all vehicles sold in California have an integrated

PCM structure that monitored all critical emis-

sions components. Manufacturers found that it

wassimplertoincorporatethissystemintoalltheir

vehicles built in the USA. In fact, by the end of

1986, most diagnostic procedures were uniform

within each manufacturer, providing an opportu-

nity for generic scan tools to come to market for

the home mechanic.

In general, a control system operates in open

loop mode only when there is no practical way to

monitor the results of an action. Example: Fuel

delivery during cold engine warm-up. The com-

puter runs in open loop mode because the

oxygen sensor is not hot enough to send a signal.

Without the sensor signal, the computer cannot

check the actual amount of fuel delivered.

KOER: Key On, Engine Running. A test mode

wherethePCMis activeandfeedingdataparam-

eters, and the engine is running. Since the

engine is running, most data parameters should

be available and accurate.

Knock: See “Detonation.”

Knock Sensor: This sensor is used to detect

engine detonation (or “knock”). When spark

knock occurs, the sensor emits a pulsing signal.

Depending on the vehicle, this signal either goes

to the PCM or a separate ESC (Electronic Spark

Control) module. Then the spark advance is

retarded until detonation stops. The sensor

contains a piezoelectric element and is threaded

into the engine block. Vibrating the element

generates the signal pulse. Special construction

O2S: Oxygen Sensor. The oxygen sensor is

threaded into the exhaust manifold, directly in the

stream of exhaust gases. The PCM uses the

sensor to “fine tune” fuel delivery. The sensor

generates a voltage of 0.6 to 1.1 volts when the

exhaust gas is rich (low oxygen content). The

voltage changes to 0.4 volts or less when the

exhaust gas is lean (high oxygen content). The

sensor only operates after it reaches a tempera-

ture of approximately 349°C (660°F).

Fuel Injector: An electronically controlled flow

valve.Fuelinjectorsareconnectedtoapressurized

fuelsupply(fuelpressureiscreatedbyafuelpump).

Noflowoccurswhentheinjectorisoff(notenergized).

Whentheinjectorisenergized,itopensfully,allowing

fueltoflow.ThePCMcontrolsfueldeliverybyvarying

theamountoftimetheinjectorsolenoidsareturnedon.

Outputs: Electrical signals sent from the PCM.

These signals may activate relays or other actua-

tors for control purposes throughout the vehicle.

The signals can also send information from the

PCM to other electronic modules, such as the

ignition or trip computer.

Solenoid: Adevicetoconvertanelectricalsignal

to mechanical movement. It consists of a coil with

a wire with a moveable metal rod in the center.

When the power is applied to the coil, the

resulting electromagnetism moves the rod and

performs some mechanical action. The PCM

often uses solenoids to switch vacuum lines on

and off. This allows the PCM to control vacuum

operated devices such as the EGR valve. Fuel

injectors are operated by another type of sole-

noid.

VIN: Vehicle Identification Number. This is the

factory-assignedvehicleserialnumber.Thisnum-

ber is stamped on a number of locations through-

out the vehicle, but the most prominent location

is on top of the dashboard on the driver’s side,

visible from outside the car. The VIN includes

information about the car, including where it was

built, body and engine codes, options, colors,

and a sequential build number. The VIN can also

tell you what adapters you may need to use the

ScanTool with your particular vehicle.

PCM: Powertrain Control Module. The “brains” of

the engine control system. It is a computer

housed in a metal box with a number of sensors

and actuators connected with a wiring harness.

Its job is to control fuel delivery, idle speed, spark

advancetiming, andemissionsystems. ThePCM

receives information from sensors, then ener-

gizes various actuators tocontroltheengine. The

PCMisfrequentlycalledtheECM(EngineControl

Module) in vehicles having other computers.

These other computers are used for climate

control, entertainment systems, transmissions,

etc.

TBI: Throttle Body Injection. A fuel injection

system having one or more injectors mounted in

a centrally-located throttle body, as opposed to

positioning the injectors close to an intake valve

port. Also called Central Fuel Injection (CFI) in

some vehicles.

WOT:Wide-OpenThrottle. Thevehicleoperating

condition brought about when the throttle is

completely (or nearly so) open. The PCM will

typically deliver extra fuel to the engine and de-

energize the A/C compressor at this time for

acceleration purposes. The PCM uses a switch

or the Throttle Position Sensor to identify the

WOT condition.

Thermistor:Aresistorwhoseresistancechanges

with temperature. Thermistors are used as sen-

sorsforvehiclecoolantandmanifoldairtempera-

ture. The resistance decreases as temperature

goes up, sending a voltage signal to the PCM

where it is converted to a temperature measure-

ment.

PROM: Programmable Read-Only Memory. A

small, replaceable electrical component hidden

behind an access door on the PCM. The PROM

contains permanent programming information

the PCM needs to operate a specific vehicle

model. Included are vehicle weight, engine and

transmission type, axle ratio, and other specifics.

ThrottleBody:Adevicewhichperformsthesame

functionasacarburetorinafuelinjectionsystem.

On a throttle body injection (TBI) system, the

throttle body is both the air door and the location

ofthefuelinjectors. Onportfuelinjectionsystems

(PFI, MPFI, SFI, etc.) the throttle body is simply

an air door. Fuel is not added until the injectors

at each intake port are activated. In each case,

the throttle body is attached to the accelerator

pedal.

Relay: A mechanical device for switching high

current circuits on and off. It is electronically

controlled by a low current circuit. Relays allow a

low power PCM signal to control a high power

device such as an electric cooling fan.

ROM: Read-Only Memory. Permanent program-

ming information stored inside the PCM, contain-

ing the information the PCM needs to operate a

specific vehicle model.

Vehicle Adapter: Like General Motors and the

ALDL connector, Ford and Chrysler use Vehicle

Adapter as the name of their diagnostic link. Ford

uses a 7-pin adapter called the EEC-IV self test

adapter. This is generally located in the engine

compartment of Ford vehicles, though specific

location varies (generally it is close to the PCM).

Sensor: Device which gives the PCM informa-

tion. The PCM can only work with electrical

signals. The job of the sensor is to take some-

thing the PCM needs to know, such as engine

temperature, and convert it to an electrical signal

that the PCM can understand. The PCM uses

sensors to measure such things as throttle posi-

tion, coolant temperature, engine speed, incom-

ing air mass and temperature, etc.

Chrysler has a similar adapter for access to the

Serial Communications Interface (SCI) diagnos-

tic program on those vehicles that support SCI.

This adapter is located on the right-hand side of

the engine compartment, and is a 6-pin configu-

ration. This adapter is usually near the Logic

Controller on the SCI computer.

SFI or SEFI: Sequential Fuel Injection or Se-

quential Electronic Fuel Injection. A fuel injection

system that uses one or more injectors for each

cylinder. The injectors are mounted in the intake

manifold, and are fired individually in the same

sequence as the spark plug firing order.

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