GM CODE READER 1.6
Contents
1. 5 1 5 2 SERVICE PROCEDURES 2 xen 5 1 You Do Plug It In e Test connector usually found under the left side of the dashboard e Set Selector switch to ECM A B position e Make sure ignition is off Plug Code Reader into test connector Read Fault Codes e Turn on ignition DO NOT START ENGINE e Read codes from flashing SERVICE 1 I ENGINE Check Engine or Service SOON Engine Soon light Pinpoint Problems e Locate fault code s in the appropriate Service Codes List Read manual for a complete description of the Code Reader and it S proper use and operation GM ii 1 1 1 YOUR VEHICLE S COMPUTER SYSTEM Today s vehicles are equipped with computer self testing abilities that can locate problems in your vehicle and store them as service codes in the vehicle s onboard computer The Code Reader allows you access to the computer s memory and recalls the service codes Instrument Panel Indicator Lights Your vehicle s Instrument panel has several indicator lights such as the Check Engine Service Engine Soon ABS Shift to D2 and Temperature indicator lights These lights do more than tell you to check for engine brake or other component malfunctions They can also transmit the service codes in the computer memory by blinking on and off SERVICE CHECK ENGINE ENGIN NOTE If your instrument panel indicator lights do not come on when you turn on the2. Fuel cutoff relay circuit open or shorted to ground Electronic spark timing EST circuit low voltage detected Electronic spark control ESC circuit problems Lean exhaust indicated Left side on dual oxygen models Rich exhaust indicated Left side on dual oxygen models Vehicle anti theft system VATS failure Power steering pressure switch failure Circuit or component problem in ECM PCM communi cation error Knock sensor module error inside computer Misfire symptom Mass air flow MAF sensor circuit error RPM is high at idle possible vacuum leak System voltage is low Computer problem faulty wrong or incorrectly installed PROM circuit or ECM PCM failure Calibration Package Chip or ECM fault or oil tem perature sensor fault low engine temperature Corvette faulty or missing PROM Calibration Package Chip ECM problem System voltage high for a long period of time System voltage too high over 17 7 volts to ECM or EGR system fault or alternator voltage not normal or Vehicle Anti Theft System fault Fuel pump circuit fault or Mixture Control M C solenoid fault or Electronic Control Module ECM fault EGR solenoid 2 failure 3 81 VIN1 Fuel pump relay GM Electronic Control Module ECM fault or oxygen sensor circuit fault or EGR solenoid 3 failure 3 8L VIN1 or fuel lean monitor Corvette 2 10 SERVICE CODE DEFINITION
3. ATS sensor signal voltage is high or low Quad Driver module or Quad driver No 1 error 2nd gear switch problem Quad Driver module or Quad driver No 2 error 3rd gear switch Quad Driver module or Quad driver No 3 error Corvette Transmission Fluid pressure switch assembly open or short circuit problems 4th gear switch Quad Driver module or Quad driver No 3 error Secondary air injection system circuit problems Manifold absolute pressure MAP sensor signal voltage is low Fuel injector Park Neutral switch circuit problems CAM sensor circuit problems Engine speed control governor malfunction Van Turbocharger wastegate overboost Wastegate electrical signal open or shorted to ground Purge solenoid voltage high carburetor engines GM Barometric pressure BARO sensor circuit failure Exhaust gas recirculation EGR valve diagnostic switch closed during engine start up or open when EGR flow requested by ECM Electronic vacuum regulator valve EVRV error EVRV controls EGR vacuum 2 8 SERVICE CODE DEFINITION Mass air flow MAF sensor signal voltage or frequency is high during engine idle Manifold absolute pressure MAP sensor signal voltage is high during engine idle Note Engine misfire or unstable idle may cause this code Mass air flow MAF sensor signal voltage or frequency is low dur
4. Coolant sensor or circuit fault signal voltage low or shorted Coolant temperature sensor or circuit fault signal voltage high Battery or alternator problem voltage too high or low Direct ignition system DIS fault line open or shorted to ground Ignition system fault loss of 2X or Low Resolution Pulse signal Transmission speed error RPM signal problem Camshaft sensor circuit problems Electronic Control Module ECM computer circuit problem Pull up resistor Saturn Camshaft or Crankshaft sensor circuit problems Fuel Injector circuit is not working properly possible blown fuel injector fuse Ignition system fault Intermittent 7X signal or loss of 58X signal or 6X signal Saturn Throttle position sensor TPS signal voltage is high Throttle position sensor TPS signal voltage is low Fuel cutoff relay circuit open or shorted to ground Manifold air temperature MAT sensor signal voltage is low or high Throttle position sensor TPS error Mixture Control M C solenoid open or short circuit problems Intake Air Temperature Sensor IAT low Retrieving ECM Codes SERVICE CODE DEFINITION Vehicle speed sensor VSS open or short circuit problems or park neutral switch circuit problem Manifold air temperature MAT sensor signal voltage is low or high Vacuum switching valve circuit open or shorted to ground
5. Vacuum sensor circuit fault or quad driver B fault 3 8L VIN1 Corrosivity add coolant Boost control problem 3 8L VIN1 Vehicle Anti Theft System fault 3 8L Transmission Temperature Sensor TTS short circuit Transmission fluid temp high Transmission Temp Sensor TTS open Transmission fluid temp low Transmission not in drive Oxygen sensor signal fault or port throttle system fault or on board cruise control fault vent solenoid circuit Air Conditioner A C system performance problems Engine oil temperature sensor fault or gear switch signal circuit fault or on board cruise control fault vacuum solenoid circuit EGR flow problem or on board cruise control problem Servo Position Sensor SPS circuit fault or Manifold Absolute Pressure MAP sensor fault or oxygen sensor fault EGR flow problem or on board cruise control problem or Manifold Absolute Pressure MAP sensor fault or oxygen sensor fault EGR flow problem or on board cruise control problem Servo Position Sensor SPS circuit fault or Manifold Absolute Pressure MAP sensor fault or oxygen sensor fault or fuel injector current low Electronic Control Module ECM computer circuit fault or air conditioning pressure sensor circuit fault or low air conditioning refrigerant charge Transmission 3 2 shift control solenoid circuit problems 2 11 Cruise control switch circuit problems
6. Air Conditioner A C pressure sensor circuit problems Torque Converter Clutch TCC solenoid circuit problems Cruise control switches circuit problems GM Retrieving ECM Codes SERVICE CODE DEFINITION On board cruise control switch circuit problems Servo Position Sensor SPS circuit fault or shorted A C clutch relay circuit Corvette or overdrive ratio error Air conditioning head pressure switch circuit fault or air conditioning pressure switch problem Torque converter clutch stuck on Air conditioning refrigerant pressure sensor circuit fault high pressure or quad driver module error Air conditioning evaporator temperature sensor circuit fault low temp Gear select switch circuit fault Corvette only Vehicle Speed Sensor VSS loss of signal Air conditioning evaporator temperature sensor circuit fault high temp Transmission Pressure control solenoid circuit problems Traction control circuit voltage low Digital EGR fault 1 solenoid or system voltage low charging system problem Transmission voltage low Digital EGR fault 2 solenoid Digital EGR fault 3 solenoid Primary cooling fan relay driver circuit circuit problems Secondary cooling fan relay driver circuit circuit problems Vehicle Speed Sensor VSS signal voltage too high Transmission Temperature Sensor TTS high temperature Vehicle Sp
7. Only work on your vehicle in a well ventilated area Put transmission in park for automatic or neutral for manual Set parking brake Put blocks on drive wheels Avoid moving fan blades or any potentially moving parts Avoid hot engine parts Turn off ignition before connecting or disconnecting any testing equipment Please read your vehicle s service manual and follow it s safety procedure 1 5 VEHICLE SERVICE MANUALS It is recommended that you consult the manufacturer s instructions and specifications in these service man uals before any test or tune up procedures are performed IMPORTANT You MUST use the PRIME CONN wiring diagrams in your vehicle s E service manual to ensure proper TYPICAL WIRING connections during testing DIAGRAM Contact your local car dealership auto parts store bookstore or public library for availability of these manuals The following companies publish valuable repair manuals 1 3 General Motors Publications Helm Inc 14310 Hamilton Ave Highland Park MI 48203 Phone 800 782 4356 Haynes Publications 861 Lawrence Drive Newbury Park California 91320 Phone 805 498 6703 Fax 805 498 2867 Mitchell International 14145 Danielson St Poway California 92064 Phone 888 724 6742 Motor Publications 5600 Crooks Road Troy Michigan 48098 Phone 800 426 6867 Fax 313 828 0215 GM General Information 1 6 PRELIMINARY VEHICLE DIAGN
8. component DO NOT replace components based only on trouble codes without first following the service procedures described in your vehicle s repair manual Most faults including those that set trouble codes are caused by damaged shorted or open wiring damaged or corroded connections improper voltages or grounds or other mechanical problems Sometimes a fault in one circuit or system will cause the computer to set a fault code for a different circuit or system Example A defective spark plug wire can cause a rich condition fault code to be set on the oxygen sensor circuit In this case replacing any component in the oxygen sensor circuit will not correct the fault because the problem is caused by the defective spark plug wire and not by the oxygen sensor circuit This is called a false code For this reason it is IMPORTANT that you make a thorough inspection of all systems wiring hoses vacuum engine mechanical charging ignition power ground fuel some of these systems are not connected to the computer system but GM 2 4 2 5 GM Retrieving ECM Codes will still affect it before retrieving trouble codes Refer to your vehicle s service repair manual for specifications and system testing procedures which apply to your particular vehicle ERASING SERVICE CODES e Always observe safety precautions before and during testing process 1 Turn off ignition 2 Remove ECM fuse from the fuse block
9. e All codes are two digits e Count blinks to get the service codes e First and second digits of code are separated by a pause Retrieving ABS Codes e Code 21 looks like O O QD CD coez BLINK BLINK BLINK NOTE Service codes will repeat as long as Code Reader is connected 6 Turn off ignition and remove the Code Reader 3 3 4 Retrieving Service Codes for Bosch 2S and 2U Systems 1 Turn off ignition 2 Connect the Code Reader to the vehicle test connector NOTE The Code Reader only fits into the connector one way EC O 3 Set Selector Switch to ABS A H position 4 Turn on ignition DO NOT START THE ENGINE 5 Read codes from the Service ABS or Anti Lock light on your vehicle s instrument panel Be sure to write the codes down NOTE If the light does not blink refer to your vehicle s service manual for information on checking the circuitry All codes are two digits Count blinks to get the service codes First and second digits of code are separated by a pause Code sequence will start with Code 12 O QD O OQ coe BLINK BLINK BLINK NOTE Code 12 is not a fault code Code 12 indicates the self diagnostic system is functioning properly system pass e Each code is repeated three times After all codes have been displayed the entire code sequence is repeated NOTE Service codes will repeat as long as Code Reader is connected 6 Turn off ignition and remove the Code R
10. if pressure exceeds a calibrated value RICH MIXTURE Air fuel mixture that has more fuel than can burn completely 1 part fuel to 14 or less parts air SAW Spark Advance Word and also Spark Angle Word SCC Spark Control Computer SES Service Engine Soon light SFI Sequential Fuel Injection type of MFI with injectors pulsed individually based on engine firing order SIG RTN Signal Return circuit for all sensors except HEGO SIL Shift Indicator Light Indicates to driver optimum time to shift gears SIR Supplemental Inflatable Restraint SIR system air bag SIS Solenoid Idle Stop SOLENOID Wire coil with a movable core which changes position by means of electromagnetism when current flows through the coil SPARK RETARD SOLENOID Output device that receives an output signal to bleed distributor s vacuum advance when spark knock occurs SSI Solid State Ignition system T V Throttle Valve TAB Thermactor Air Bypass solenoid TACH INPUT Engine rpm signal sent to computer from ignition coil primary circuit TAD Thermactor Air Diverter solenoid TBI Throttle Body Injection Fuel TCC Torque Converter Clutch TCP Temperature Compensating Pump TDC Top Dead Center THERMACTOR AIR CONTROL VALVE Combines function of a normally closed air bypass valve and an air diverter valve in one integral valve THERMACTOR AIR SYSTEM Efficiency of catalytic converter
11. is dependent upon temperature and chemical makeup of exhaust gases These requirements are met by the thermactor air supply system THREE WAY CATALYST Combines 2 converters in 1 shell Controls NOx HC and CO Also called dual catalytic converter TIMING Relationship between spark plug firing and piston position TKS Throttle Kicker Solenoid when energized supplies manifold vacuum to throttle kicker actuator as directed by computer to compensate for engine loads Also called idle up system TOT Transmission Oil Temperature sensor TP or TPS Throttle Position Sensor or its circuit Used to signal computer the position of the throttle plates TPI Tuned Port Injection a type of MFI with intake tubes designed to be tuned for performance Most TPI engines are also SFI TTS Transmission Temperature Switch TVS Temperature Vacuum Switch TVV Thermal Vent Valve TWC Three Way Catalyst VACUUM A term to describe a pressure that is less than atmospheric pressure VACUUM ADVANCE Advances ignition timing with relation to engine load or computer signals VAF Vane Air Flow sensor or its circuit VAT Vane Air Flow Temperature sensor VATS Vehicle Anti theft System VCM Vehicle Control Module VM Vane Meter or air flow meter VSS Vehicle Speed Sensor WOT Wide Open Throttle or Wide Open Throttle switch WSS Wheel Speed Sensor GM GM 4 10 5 5 1 5 2 LIMITED ONE YEAR WARRA
12. or open Coolant sensor signal unstable Coolant Transmission temperature sensor ratio error 3rd line circuit shorted 3rd gear stuck on Air temperature sensor signal 4th line circuit grounded or open Throttle position sensor TPS to manifold absolute pressure MAP sensor voltage out of range 4th line circuit shorted 4th gear stuck on Torque Converter Clutch TCC circuit grounded or open Torque Converter Clutch TCC circuit shorted Transaxle temperature unstable Transaxle temperature low Low coolant Brake switch stuck open Brake switch stuck closed Engine speed invalid Torque Converter Clutch TCC hold circuit grounded or open Torque Converter Clutch TCC hold circuit shorted Master relay stuck on Assembly Line Diagnostic Link ALDL Clamp circuit intermittent fault Torque Converter Clutch TCC hold circuit intermittent fault Master enable relay circuit intermittent fault Line circuit intermittent fault Torque Converter Clutch TCC circuit intermittent fault 2nd gear circuit intermittent fault 9rd gear circuit intermittent fault GM 4th gear circuit intermittent fault 2 16 3 3 1 3 1 1 3 1 2 3 1 3 3 1 4 3 2 ANTILOCK BRAKE SYSTEMS ABS What is ABS The ABS system utilizes several mechanical hydraulic and electric electroni
13. which codes are intermittent faults 7 Turn on ignition start engine and observe Service Engine Soon light light should turn off Run engine for several minutes to allow engine to reach normal operating temperature then observe Service Engine Soon light If Service Engine Soon light turns on turn off ignition and repeat steps 2 through 5 This reveals hard fault codes 2 A 2 3 1 NOTE It may be necessary to test drive the vehicle to reset hard fault codes 13 15 24 44 45 and 55 after they have been erased If Service Engine Soon light does not turn on the initial stored fault codes were all intermittent fault codes Refer to the Diagnostic Procedures section in the manufacturer s service manual for your vehicle 8 Follow the testing and repair procedures outlined in the manufacturer s service manual for your vehicle to correct hard faults Codes should be addressed and eliminated in the order they were received erasing and retesting after each repair is made to be sure the fault was eliminated Code 12 will appear alone when no other fault codes are present NOTE Whenever codes 51 52 54 or 55 are displayed with other codes troubleshoot and eliminate the 50 Series codes first then proceed with the lower numbered codes 9 Turn off ignition and remove the Code Reader Servicing Fault Codes Diagnostic trouble codes indicate a problem in a circuit not necessarily a faulty
14. 00 Lemans J Parisienne Phoenix Safari Safari Wagon Sunbird T 1000 Saturn Trucks and Vans All models All one ton capacity or less with gas engines Buick Roadmaster 5 7 liter Chevrolet Camaro 3 4 liter 5 7 liter Caprice 5 7 liter Caprice 5 7 liter Cavalier 3 1 liter Lumina 3 1 liter Pontiac Firebird 3 4 liter 5 7 liter Sunbird 2 0 liter 3 1 liter Saturn All models Trucks and Vans All one ton capacity or less with gas engines GM Retrieving ECM Codes Make Model Chevrolet Caprice 4 3 liter Saturn All models Trucks All one ton capacity or less with gas and Vans engines EXCEPT S T Series vehicles Not applicable to models equipped with climate control computers NOTE For 1994 and 1995 vehicles only the models listed above are compatible with the Code Reader The Code Reader is not compatible with 1996 and later model year vehicles 24 1 Vehicle Test Connector GM and Saturn vehicles use one of two types of test connectors 12 pin or 16 pin 12 Pin Connector The 12 pin connector was phased out completely in 1996 Some 1994 and 1995 vehicles still use the 12 pin connector but because of changes in the ECM the Code Reader is not compatible with some of these systems see paragraph 2 1 B 16 Pin Connector The new 16 pin connector was introduced on some 1994 and 1995 models and was made stan
15. Codes Year Model ABS Type 1989 93 Astro G Series Van R and V Series Kelsey Hayes Trucks Safari Suburban RWAL 1987 94 Blazer C and K Series Pickup Sierra Kelsey Hayes S and T Series Pickup EXCEPT RWAL 93 94 4 3L M T 1989 90 Eldorado Reatta Riviera Seville Toro Teves II nado Delta 88 Bonneville DeVille Electra Le Sabre Ninety Eight Fleet wood Park Avenue Touring Sedan EXCEPT 1988 Eldorado Reatta Riviera Seville Toronado 1990 91 Corvette Bosch 28 1990 92 Brougham Bosch 2U 1990 94 Astro Bravada Jimmy Safari Sierra Kelsey Hayes Sonoma Suburban Cyclone Typhoon 4WAL Yukon C and K Series Blazer and Pickup S and T Series Blazer and Pickup G Series Van Astro C and K Series Pickup G Kelsey Hayes Series Van Safari Sierra Suburban 4WAL Tahoe Yukon 1991 92 Custom Cruiser Eldorado Seville Bosch 2U Reatta Toronado Trofeo 1991 93 Riviera Roadmaster Caprice Bosch 2U 1993 Eldorado Seville Bosch 2U ABS TCS 3 3 RETRIEVING SERVICE CODES e Always observe safety precautions before and during testing process e Fixany known mechanical problems before this test e Have pencil and paper handy 1 Determine your vehicle s ABS Type paragraph 3 1 and retrieve codes using the appropriate procedures Teves II Paragraph 3 3 1 Kelsey Hayes RWAL Paragraph 3 3 2 Kelsey Hayes 4WAL Paragraph 3 3 3 Bosch 28 Para
16. E CONTROL MODULE A microprocessor based device which contains electronic circuitry to control and monitor air fuel and emission systems and aid in diagnostics EPC Electronic Pressure Control solenoid EPROM Erasable Programmable Read Only Memory ERS Engine RPM Sensor ESA Electronic Spark Advance ESC Electronic Spark Control EST Electronic Spark Timing EVP EGR Valve Position sensor or its circuit EVR EGR Vacuum Regulator or its circuit EVRV Electronic Vacuum Regulator Valve Controls EGR vacuum EXHAUST GAS OXYGEN SENSOR Sensor that changes its voltage output as exhaust gas oxygen content changes as compared to oxygen content of the atmosphere The constantly changing electrical signal is used to control fuel mixture EXHAUST GAS RECIRCULATION Procedure where a small amount of exhaust gas is re admitted to combustion chamber to reduce peak combustion temperatures thus reducing NOx FAIL SAFE or Fail Soft any attempt by a computer to compensate for a fault or lost signal usually by substituting fixed replacement valves FEEDBACK CARBURETOR FBC System of fuel control employing a computer controlled solenoid that varies the carburetors air fuel mixture FMEM Failure Mode Effects Management Sometimes referred to limp in mode GND GRD or GRND Ground Common line leading to the negative side of the battery HALL EFFECT Process where current is passed through a small slice of semi condu
17. GM Retrieving ABS Codes 3 5 3 Kelsey Hayes 4WAL System Service Codes Code Service Code Definition System Normal System Normal 2WD n 12 13 14 21 22 23 25 26 27 28 29 31 2 5 6 7 8 1 2 3 4 5 6 T 8 9 Erratic right front speed sensor Left front speed sensor fault Missing left front speed signal Simultaneous loss of both front sensor signals Simultaneous drop out of all 4 sensors Right rear speed sensor fault 3 Missing right rear speed signal Erratic right rear speed sensor Erratic left front speed sensor Left rear speed sensor fault or VSS circuit open 1993 3 3 3 Erratic left rear speed signal or erratic VSS signal 1993 Wheel speed error 3 50 4 Wheel Anti Lock 4WAL control unit fault GM 3 12 Missing left rear speed signal or VSS signal missing 1993 4 4 4 4 4 4 4 4 4 51 52 53 54 60 4 Wheel Anti Lock AWAL control unit fault 66 4 Wheel Anti Lock AWAL control tw 68 Locked motor or shorted motor cireuit 86 Shorted antilock warning lamp 3 5 4 Bosch 2S System Service Codes 3 13 GM Retrieving ABS Codes Pump motor or motor relay fault Solenoid valve relay fault Electronic Brake Control Module EBCM fault Serial data link fault 75 Lateral accelerometer fault short to battery ground or open circuit 76 Lateral accelerometer fault signal out of range or incorrect 3 5 5 Bosch 2U Syst
18. GM CODE READER 1 6 995 282 Domestic Cars and Trucks SAVE TIME AND MONEY BY IDENTIFYING ENGINE PROBLEMS YOURSELF e COMPUTER SAFE NO BATTERY REQUIRED FOR GENERAL MOTORS AND SATURN VEHICLES FROM 1982 TO 1995 EXCLUDING CADILLAC GM lnnova 1998 Table of Contents Paragraph Title Page No XOU CAN DOLET epe oreet io e eere ter nets ii GENERAL INFORMATION 1 1 YOUR VEHICLE S COMPUTER SYSTEM 1 1 1 2 ABOUT YOUR CODE READER 1 2 1 3 TEST CONNECTOR LOCATIONS 1 2 1 4 SAFETY PRECAUTIONS eee 1 3 1 5 VEHICLE SERVICE MANUALS t 1 3 1 6 PRELIMINARY VEHICLE DIAGNOSIS 1 4 WORKSHEET RETRIEVING ECM CODES 2 1 VEHICLES COVERED een 2 1 2 2 BEFORE YOU BEGIN 2 erste anis 2 2 2 3 RETRIEVING SERVICE CODES 2 3 2 4 ERASING SERVICE CODES c 2 6 2 5 ECM SERVICE CODES c 2 6 RETRIEVING ABS CODES 3 1 ANTI LOCK BRAKE SYSTEMS 3 1 3 2 APPLICATIONS ttti tco 3 1 3 8 RETRIEVING SERVICE CODES 3 2 3 4 ERASING SERVICE CODES 3 7 3 5 ABS SERVICE CODES 3 9 GLOSSARY 4 1 INTRODUCTION 4 1 4 2 GLOSSARY OF TERMS AND 4 1 ABBREVIATIONS WARRANTY AND SERVICE 5 1 LIMITED ONE YEAR WARRANTY
19. NTY The Manufacturer warrants to the original purchaser that this unit is free of defects in materials and workmanship under normal use and maintenance for a period of one 1 year from the date of original purchase If the unit fails within the one 1 year period it will be repaired or replaced at the Manufacturer s option at no charge when returned prepaid to the Service Center with Proof of Purchase The sales receipt may be used for this purpose All replacement parts whether new or re manufactured assume as their warranty period only the remaining time of this warranty This warranty does not apply to damage caused by improper use accident abuse improper voltage service fire flood lightning or other acts of God or if the product was altered or repaired by anyone other than the Manufacturer s Service The Manufacturer under no circumstances shall be liable for any consequential damages for breach of any written warranty of this unit This warranty gives you specific legal rights and you may also have rights which vary from state to state This manual is copyrighted with all rights reserved No portion of this document may be copied or reproduced by any means without the express written permission of the Manufacturer THIS WARRANTY IS NOT TRANSFERABLE For service send via U P S if possible prepaid to manufacturer Allow 3 4 weeks service time SERVICE PROCEDURES If you have any questions please contac
20. OSIS WORKSHEET The purpose of this form is to help you gather preliminary information on your vehicle before you retrieve codes By having a complete account of your vehicle s current problem s you will be able to systematically pinpoint the problem s by comparing your answers to the fault codes you retrieve You can also provide this information to your mechanic to assist in diagnosis and help avoid costly and unnecessary repairs It is important for you to complete this form to help you and or your mechanic have a clear understanding of your vehicle s problems NAME DATE VIN YEAR MAKE MODEL ENGINE SIZE VEHICLE MILEAGE VIN Vehicle Identification Number found at the base of the windshield on a metallic plate or at the driver door latch area consult your vehicle owner s manual for location TRANSMISSION Q Automatic Q Manual Please check all applicable items in each category DESCRIBE THE PROBLEM GM 1 4 1 WHEN DID YOU FIRST NOTICE THE PROBLEM Q Just Started Q Started Last Week Q Started Last Month Other LIST ANY REPAIRS DONE IN THE PAST SIX MONTHS PROBLEMS STARTING C No symptoms Cranks but will not start Will not crank Starts but takes a long time ENGINE QUITS OR STALLS No symptoms Right after vehicle comes to a stop Q Right a
21. Reader is a device which connects to your vehicle s computer self test connector It allows the computer to output the service codes through the vehicle s instrument panel indicator lights The Code Reader can be used to retrieve B Engine Electronic Transmission codes ECM PCM NOTE Unless otherwise indicated any reference to ECM throughout this manual also applies to PCM Anti Lock Brake System codes ABS Controls and Indicators Selector Switch Selects operating mode for Code Reader ECM A B Use to retrieve ECM TT codes DE READER E B ABS A H Use to retrieve ABS service codes TEST CONNECTOR LOCATIONS e The gateway to your vehicle s onboard computer Your vehicle test connector also known as the Assembly Line Data Link ALDL connector or Assembly Line Communication Link ALCL connector is usually black in color and is most likely found under the left side of the dashboard Some connectors can be found on the right kick panel under the center of the dashboard on the side of the fuse block or under the ashtray in the center console The connector might have a plastic cover on it labeled Diagnostic Connector If you have any questions about the connector s location please refer to your vehicle s service manual for detailed information 1 1 4 SAFETY PRECAUTIONS o erpe Always observe safety precautions whenever working on a vehicle Always wear safety eye protection
22. c components to automatically control hydraulic brake pressure to the rear or front and rear wheels depending on the brake system to prevent wheel lock up during hard braking What are the benefits of ABS By preventing wheel lock up during hard braking ABS helps maintain vehicle directional stability as well as driver control ensuring a safer and more controlled stop in the shortest distance How does the ABS system work The ABS system utilizes a computer called an Electronic Brake Control Module EBCM The system also employs several sensors and switches which monitor and control wheel speed and hydraulic brake pressure when hard braking is applied When the wheel speed sensor s detect a potential lock up condition a signal is sent to the EBCM The EBCM in turn sends a signal to the hydraulic system to relieve brake pressure at the affected wheels preventing the lock up condition What is the purpose of the Code Reader Most ABS systems generate diagnostic service codes when a fault in the system is detected These service codes are stored in the EBCM The Code Reader allows you to access the EBCM s memory and recalls the service codes The EBCM outputs the service codes through the Anti Lock light on the vehicle s instrument panel APPLICATIONS GM vehicles use a variety of Anti Lock Brake Systems This Code Reader may be used to retrieve ABS service codes from the following vehicle models GM Retrieving ABS
23. cle s instrument panel Be sure to write the codes down NOTE If the light does not blink refer to your vehicle s service manual for information on checking the circuitry GM Retrieving ABS Codes All codes are two digits Count blinks to get the service codes First and second digits of code are separated by a 3 second pause Second digit of service code is followed by a termination code Anti Lock light remains steady on NOTE DO NOT count termination code as part of second digit Code 13 looks like CD amp O O O Code 13 BLINK BLINK BLINK BLINK TERMINATION CODE Up to seven codes can be stored by the EBCM To check for additional codes with ignition still on disconnect and then reconnect Code Reader Repeat this procedure until all codes have been retrieved NOTE Service codes cannot be erased until all stored service codes have been retrieved 8 Turn off ignition and remove the Code Reader 3 3 2 Retrieving Service Codes for Kelsey Hayes RWAL Systems Turn off ignition Connect the Code Reader to the vehicle test connector NOTE The Code Reader only fits into the connector one way Set Selector Switch to ABS A H position Turn on ignition DO NOT ABS A H START THE ENGINE CODE READER NOTE There is a 20 second pause before service codes begin to display Read codes from the Brake light on your vehicle s instrument panel Be sure to write th
24. ctor material at the same time as a magnetic field to produce a small voltage in the semiconductor HARD FAULT Fault present during current engine operating cycle Opposite of an intermittent fault which does not stay present HEDF High speed Electro Drive Fan relay or its circuit HEGO Heated Oxygen Sensor or its circuit HIC Hot Idle Compensator GM GM Glossary HPA High Pressure Accumulator IAC Idle Air Control IAS Inlet Air Solenoid valve or its circuit IAT Intake air temperature sensor performs same function as MAT sensor ICM Integrated Control Module IDLE TRACKING SWITCH An input device that sends a signal to the computer to indicate a closed throttle condition IGN Ignition INTERMITTENT FAULT Fault which occurred during a previous engine operating cycle Intermittent fault may have set a fault code which is still present in PCM memory ISA Idle Speed Actuator Extends or retracts to control engine idle speed and to set throttle stop angle during deceleration ISC Idle Speed Control either computer control motor air bypass valve or any device used to control idle rpm ISO VALVE Isolation Valve ITS Idle Tracking Switch KAM Keep Alive Memory Battery power memory locations in computer used to store failure codes and some diagnostic parameters KAPWR Keep Alive Power used to power KAM circuit of the processor KNOCK SENSOR KS Input device that responds
25. dard equipment on all 1996 and subsequent model year vehicles The Code Reader will not work on vehicles equipped with the 16 pin connector 2 2 BEFORE YOU BEGIN e Fix any known mechanical problems before performing any test Make a thorough check before starting any test procedure Loose or damaged hoses wiring or electrical connectors are often responsible for poor engine performance and in some cases they may cause a false fault code GM 2 2 Please read your vehicle s service manual for proper connection of vacuum hoses electrical wiring and wiring harness connectors Check the following areas a rrperpep All fluid levels Air cleaner and ducts Belts Mechanical linkage associated with sensor Vacuum hoses Spark plugs and wires Electrical wiring Electrical connectors Proper battery voltage Fuel system components 2 3 RETRIEVING SERVICE CODES 1 2 Always observe safety precautions before and during the testing process Fix any known mechanical problems before this test Have pencil and paper handy Turn off ignition Connect the Code Reader to the vehicle test connector NOTE The Code Reader only fits into the connector one way WEIL C CO Set Selector Switch to ECM A B position ECM A B Turn on ignition DO NOT ABS A H START THE ENGINE CODE READER Mu rn Read codes from the Check Engine or Serv
26. e codes down NOTE If the light does not blink refer to your vehicle s service manual for information on checking the circuitry e Count blinks to get the service codes e Codes may be one or two digits e Codes are displayed as a pattern of one long blink followed by one or more short blinks Count ALL blinks to get code e Code 8 looks like ED O LONG SHORT SHORT BLINK BLINK BLINK e The EBCM stores only one service code at a a time even though it may detect more than one fault condition The first fault detected results in a stored service code The detected fault must be corrected and the service code must be erased from the computer s memory before additional codes can be stored e After the first fault is corrected and the service code is erased drive the vehicle at a speed greater than 35 mph to set any additional service codes 3 3 3 Retrieving Service Codes for Kelsey Hayes 4WAL Systems 1 Turn off ignition 2 Connect the Code Reader to the vehicle test connector NOTE The Code Reader only fits into the connector one way Il EEL C 10E 3 Set Selector Switch to ABS A H position 4 Turn on ignition DO NOT ABS A H START THE ENGINE CODE READER 5 Read codes from the Anti Lock light on your vehicle s instrument panel Be sure to write the codes down NOTE If the light does not blink refer to your vehicle s service manual for information on checking the circuitry
27. eader GM 3 6 3 3 4 3 4 1 3 4 2 ERASING SERVICE CODES e Always observe safety precautions before and during testing process e Erase codes only when all repairs have been completed Determine your vehicle s ABS Type paragraph 3 2 and erase codes using the appropriate procedures 3 4 1 Teves II 3 4 2 Kelsey Hayes RWAL 3 4 3 Kelsey Hayes 4WAL 3 4 4 Bosch 28 3 4 5 Bosch 2U Erasing Service Codes for Teves II Systems 1 Drive vehicle at a speed greater than 20 MPH Service codes will automatically be cleared 2 Repeat procedure for retrieving service codes paragraph 3 3 1 to make sure codes have been erased and no new codes have been recorded Erasing Service Codes for Kelsey Hayes RWAL Systems For all vehicle models EXCEPT C and K 3500 Series Heavy Duty HD 1992 93 1 Turn offignition 2 Remove STOP HAZARD fuse from fuse block 3 Wait 20 seconds then reinstall STOP HAZARD fuse 4 Repeat steps 2 and 3 for each code stored For example if four codes were retrieved remove and install STOP HAZARD fuse four times 5 Repeat procedure for retrieving service codes paragraph 3 3 2 to make sure codes have been erased For C and K 3500 Series Heavy Duty HD 1992 93 vehicles ONLY 1 Turn offignition 2 Remove STOP HAZARD fuse from fuse block 3 Turn on ignition and observe Brake light If Brake light is ECM A B on a code s is stored 4 Set Selector Sw
28. eed Sensor VSS signal voltage too low transmission component fault GM QDM Solenoid B monitored voltage differs from commanded Anti Lock Brake System ABS message fault Saturn Brake switch circuit problems 2 12 SERVICE CODE DEFINITION Internal PCM communication fault Saturn or QDM Solenoid A monitored voltage differs from commanded Ignition system fault 3X signal problem Torque Converter Clutch TCC solenoid circuit problems Reverse Inhibit open or short circuit in reverse inhibit solenoid 3 2 Control solenoid open or short circuit problems Skip shift solenoid open or short circuit problems Programmable Read Only Memory error or undefined gear ratio input or output sensor failure Torque converter clutch TCC TCC is mechanically stuck on Analogue Digital Electronic Control Module ECM error or shift Solenoid B stuck on Electrically Erasable Programmable Read Only Memory EEPROM error or shift Solenoid B stuck off or high gear ratio error Electronic Control Module ECM computer circuit fault Power Management fault TCC error Skip shift light open or short circuit problems in skip shift light circuit Pressure control solenoid transmission line pressure not at desired level Change oil light wrong voltage is present in light circuit for more than 26 seconds Transmission voltage low low system vo
29. em Service Codes Code Service Code Definition Right front wheel sensor fault Right front toothed wheel frequency error Left front wheel sensor fault R 41 45 55 61 63 71 72 Left front toothed wheel frequency error Rear axle speed sensor fault ar axle toothed wheel frequency error Right front solenoid valve fault 12 21 22 25 26 35 36 41 45 Left front solenoid valve fault Left front solenoid valve at 55 61 63 71 72 GM 3 14 4 4 1 4 2 INTRODUCTION The Society of Automotive Engineers has issued a Standard SAE J1930 for Electrical Electronic Systems Diagnostic Terms Definitions Abbreviations and Acronyms However at the present time this Standard is not in wide use by vehicle manufacturers This Glossary contains definitions for abbreviations and terms you may find in this manual or in your vehicle service manual These definitions may not agree with those contained in SAE J1930 GLOSSARY OF TERMS AND ABBREVIATIONS A C Air Conditioning AAC Auxiliary Air Control Valve ABS Anti Lock Brake System ACC Air Conditioning Clutch compressor signal input to computer relating status of air conditioning clutch ACCS Air Conditioning Cycling Switch ACD Air Conditioner Demand switch ACT Air Charge Temperature sensor or signal circuit ACV Thermactor Air Control Valve AIR Air Injector Reaction system airflow from pump is directed into engine reduce e
30. fter starting Q While idling When shifting into gear During acceleration During steady speed driving When parking IDLING CONDITIONS No symptoms Is sometimes too fast or too slow Is too slow at all times Is rough or uneven L Is too fast Fluctuates up and down RUNNING CONDITIONS No symptoms Backfires Runs rough C Misfires or cuts out C Lacks power Q Engine knocks pings or rattles Bucks and jerks Q Surges Poor fuel economy C Dieseling or run on Hesitates or stumbles on accelerations 1 5 GM General Information AUTOMATIC TRANSMISSION PROBLEMS if applicable C No symptoms Q Vehicle does not move when in Shifts too early or too late gear Q Changes gear incorrectly Jerks or bucks PROBLEM OCCURS Morning Afternoon C Anytime ENGINE TEMPERATURE WHEN PROBLEM OCCURS Cold Warm Q Hot DRIVING CONDITIONS WHEN PROBLEM OCCURS Q Short less than 2 miles With headlights on 2 10 miles Q During acceleration Long more than 10 miles Q Mostly driving downhill Stop and go Q Mostly driving uphill Q While turning Mostly driving level Q While braking Mostly driving curvy roads C At gear engagement Mostly driving rough roads Q With A C operating DRIVING HABITS Q Mostly city driving Q Highway Park vehicle inside Park vehicle outside Drive less than 10 miles per day Drive 10 to 50 miles per day Drive more than 50 mi
31. g directs airflow to catalytic converter or exhaust ports of the engine EBCM Electronic Brake Control Module ECM Engine Control Module properly call a Powertrain Control Module ECT Engine Coolant Temperature sensor or circuit ECU Electronic Control Unit To process input information to trigger ignition control module EDF Electro Drive Fan relay or its circuit EECS Evaporative Emission Control System EEGR Electronic Exhaust Gas Recirculation valve Sonic EEPROM Electronically Erasable Programmable Read Only Memory EET Electronic Exhaust Gas Recirculation Transducer EFC Electronic Feedback Carburetor Utilizes an electronic signal generated by an exhaust gas oxygen sensor to precisely control air fuel mixture ratio in the carburetor EFI Electronic Fuel Injection Computer controlled fuel injection system EGO Exhaust Gas Oxygen sensor EGR Exhaust Gas Recirculation system is designed to allow flow of inert exhaust gases into combustion chamber to cool combustion and reduce nitrous oxides in exhaust EHC Exhaust Heat Control vacuum solenoid or its circuit EHCU Electro Hydraulic Control Unit EIC Electronic Instrument Cluster ELECTRONIC SPARK CONTROL Used to retard spark advance if detonation occurs ELECTRONIC SPARK TIMING PCM controlled timing of the ignition spark EMI Electro Magnetic Interference EMR Electronic Module Retard controls spark retard ENGIN
32. graph 3 3 4 Bosch 2U Paragraph 3 3 4 Be sure to write codes down GM 3 2 After retrieving ABS fault codes erase codes using the appropriate procedures for your vehicle and ABS system paragraph 3 4 Repeat the procedure to retrieve ABS fault codes step 1 above NOTE It may be necessary to perform a thorough test drive 4 to reset some fault codes In most cases codes which reappear indicate hard faults Codes which DO NOT reappear are usually intermittent faults Follow the testing and repair procedures outlined in the manufacturer s service manual for your vehicle to correct hard faults Codes should be addressed and eliminated in the order they were received erasing and retesting after each repair is made to be sure the fault was eliminated 3 3 1 Retrieving Service Codes for Teves Il Systems 1 2 3 Turn on ignition DO NOT START THE ENGINE Observe Anti Lock light If Anti Lock light turns off within 30 seconds no ABS service codes have been stored B If Anti Lock light remains on longer than 30 seconds continue to step 2 to retrieve ABS service codes Turn off ignition Connect the Code Reader to the vehicle test connector NOTE The Code Reader only fits into the connector one way EET CO TIRE Set Selector Switch to ABS A H ECM A B position Turn on ignition DO NOT ABS START THE ENGINE CODE READER Read codes from the Anti Lock light on your vehi
33. graph 3 5 1 Kelsey Hayes RWAL Paragraph 3 5 2 Kelsey Hayes 4WAL Paragraph 3 5 3 Bosch 28 Paragraph 3 5 4 Bosch 2U Paragraph 3 5 5 GM Retrieving ABS Codes 3 5 1 Teves System Service Codes n n n m 25 26 27 n 3 T 56 m ss a D E m 15 6 is d 52 53 55 56 s GM 3 10 Left rear Wheel Speed Sensor 3 5 2 Kelsey Hayes RWAL System Service Codes Service Code Definition 1 Rear Wheel Anti Lock RWAL Electronic Control Unit ECU malfunction or improper voltage Open isolation valve or faulty ECU Open dump valve or faulty ECU Grounded anti lock valve reset switch circuit anti lock valve reset switch circuit 4 Grounded anti lock valve reset switch circuit E Excessive actuation of the dump valve during an anti lock 6 7 8 9 Erratic speed signal Shorted isolation valve circuit or faulty ECU Shorted dump valve circuit or faulty ECU Open or grounded circuit to the vehicle speed sensor Brake lamp switch circuit fault Rear Wheel Anti Lock RWAL Electronic Control U ECU malfunction or improper voltage 12 Rear Wheel Anti Lock RWAL Electronic Control Uni ECU malfunction or improper voltage 13 Rear Wheel Anti Lock RWAL Electronic Control Uni ECU malfunction 14 Rear Wheel Anti Lock RWAL Electronic Control Uni ECU malfunction ECU malfunction Rear Wheel Anti Lock RWAL Electronic Control Uni 3 11
34. ice Engine Soon light from the Shift to D2 light 1991 and 1992 models or the Temperature indicator light 1993 and subsequent for Saturn Electronic Transmission codes on your vehicle s instrument panel Be sure to write the codes down NOTE If the light does not blink refer to your vehicle s service manual for information on checking the circuitry All codes are two digits GM Retrieving ECM Codes e Each code is transmitted three times before the next code is sent e Code sets will begin with Code 12 System Pass even if fault codes are present e The codes will continue to be sent as long as the ignition is on and the Code Reader is connected Count blinks to get the service codes Code 12 looks like O QD O CD c 12 BLINK BLINK BLINK NOTE Code 12 is not a fault code Code 12 indicates the computer s self diagnostic system is functioning properly SYSTEM PASS If code 12 is the only code which displays when you perform the diagnostic test this means there are no fault codes stored in the vehicle s computer Consult your vehicle s repair manual for no codes problems e Code 22 looks like O O QD C9 DO coez BLINK BLINK BLINK BLINK IMPORTANT Any code that ends in zero 0 is transmitted as follows e Code 30 looks like CES code BLINK BLINK BLINK 6 Next erase service codes see paragraph 2 4 This will help you determine which codes are hard faults and
35. ignition please refer to your vehicle s service manual You may have problems in the car s circuitry You must fix these problems before you can obtain service codes from the vehicle s onboard computer 1 1 2 Service Codes 1 1 The service codes are also called fault codes diagnostic codes or trouble codes These codes can be used to identify systems or components which are malfunctioning The computer records codes for two types of problems B Hard Codes Hard codes are stored for problems which are happening now The instrument panel indicator light will stay on when the engine is running B Intermittent Codes or Continuous Memory Codes Intermittent service codes are stored in the computer s memory for problems which occur intermittently or for problems which happened in the past but are not currently present Intermittent problems may cause the panel indicator light to flicker or to turn on intermittently Intermittent codes are stored in the computer s memory for a set period of time usually 50 start cycles If an intermittent problem does not recur within this time period the computer automatically erases the related intermittent fault code from it s memory GM 1 2 1 2 1 1 3 GM General Information NOTE For Saturn vehicles either the Shift to D2 light or the Temperature indicator light is used to transmit Saturn Electronic Transmission codes ABOUT YOUR CODE READER The Code
36. ing engine cruise Manifold absolute pressure MAP sensor signal voltage is low during ignition on Pressure sensor circuit signal voltage too high or low carburetor engines Idle air control IAC system problem can not set desired RPM or idle speed actuator ISA carbureted system problems Mass air flow MAF sensor burn off circuit problem Transmission shift problem electronically controlled transmissions only Direct ignition system DIS fault loss of 24X signal or extra or missing pulses in electronic spark timing EST signal Ignition system fault loss of High Resolution Pulse signal Brake switch stuck on Brake switch circuit fault Knock sensor KS open circuit problem Torque converter clutch TCC circuit fault Clutch switch circuit problems Knock sensor KS short circuit problem Cam sensor CAM failure Cylinder select error Tach input error no reference pulses during engine run Electronic spark timing EST circuit open or shorted to ground during engine run Direct ignition system DIS fault bypass circuit open or shorted to ground during engine run Ignition system fault loss of 1X Reference Pulse signal Retrieving ECM Codes SERVICE CODE DEFINITION Electronic spark timing EST circuit open or shorted Direct ignition system DIS fault bypass circuit open or shorted to ground during engine run
37. itch to ABS A H ABS A H position CODE READER GM 3 4 3 Erasing Service Codes for Kelsey Hayes 4WAL Systems Retrieving ABS Codes Connect the Code Reader to the vehicle test connector for one second remove the Code Reader for one second reconnect the Code Reader for one second then remove the Code Reader Turn off ignition Reinstall STOP HAZARD fuse in fuse block Repeat procedure for retrieving service codes paragraph 3 3 2 to make sure codes have been erased Turn on ignition Set Selector Switch to ABS A H position Connect the Code Reader to the vehicle test connector for two seconds remove the Code Reader for one second reconnect the Code Reader for two seconds then remove the Code Reader The Anti Lock and Brake light should BOTH light then turn off This indicates service codes have been erased Turn off ignition Repeat procedure for retrieving service codes paragraph 3 3 3 to make sure codes have been erased 3 4 4 Erasing Service Codes for Bosch 2S Systems GM Turn off ignition Set Selector Switch to ABS A H ECM A B position ABS A H Connect the Code Reader to the HN vehicle test connector Ji CODE READER Turn on ignition Service ABS light will begin displaying service codes Remove the Code Reader for one second then reconnect the Code Reader for at least one second Repeat step 5 three more times a total of four times wi
38. les per day GASOLINE USED Q 87 Octane Q 91 Octane Q 89 Octane More than 91 Octane WEATHER CONDITIONS WHEN PROBLEM OCCURS 32 55 0 13 Above 55 13 C Below freezing 32 F 0 C CHECK ENGINE LIGHT DASH WARNING LIGHT Sometimes ON C Always Never ON PECULIAR SMELLS Q Hot Gasoline Sulfur rotten egg Q Burning oil Q Burning rubber Q Electrical STRANGE NOISES Rattle Q Squeak Q Knock Other GM 1 6 2 2 1 VEHICLES COVERED This Code Reader may be used to retrieve engine service codes from most General Motors GM and Saturn domestic cars and trucks EXCEPT Geo Nova and Sprint Includes all models EXCEPT Cadillacs and diesel vehicles Specific makes and models are listed below Model Year Model 1982 93 Century Electra Electra Wagon Estate Wagon Le Sabre Le Sabre Wagon Park Avenue Reatta Regal Grand National Riviera Roadmaster Skyhawk Skylark Somerset Chevrolet Berreta Camaro Caprice Cavalier Cele brity Chevette Citation Corisca Corvette El Camino Impala Lumina Monte Carlo Oldsmobile Achieva Calais Custom Cruiser Cutlass Calais Ciera Cutlass Cruiser Cruiser Wagon Cutlass Supreme Supreme Classic Delta 88 Eighty eight Firenze Ninety eight Omega Toronado Touring Sedan Trofeo Pontiac 6000 6000 STE Bonneville Fiero Firebird Grand Am Grand Prix J 20
39. ltage possibly caused by generator voltage supply circuit or power train control module Low oil light wrong voltage is present in light circuit for more than 26 seconds Vehicle speed sensor VSS output circuit problems Tachometer output circuit problems 2 13 GM Retrieving ECM Codes 2 5 2 Saturn Electronic Transmission Service Codes Transmission codes will be transmitted if present after all engine codes are transmitted and code 11 has been sent Code 11 indicates that transmission codes are present and will be transmitted on the Shift to D2 light 1991 92 models or the Temperature indicator light 1993 and later models SERVICE CODE DEFINITION Line pressure high Line pressure low Hot light No 1st gear Electrical variable orifice EVO fault No gears available 2nd gear stuck on No 2nd gear No 3rd gear No 4th gear No torque converter clutch Torque converter clutch stuck on Quick quad driver output fault Transaxle temperature circuit open Transaxle temperature circuit grounded Powertrain Control Module PCM communication failure No turbine speed signal Turbine speed signal noise Vehicle Speed Sensor VSS circuit no signal Vehicle Speed Sensor VSS circuit signal noise Master relay open or grounded Master relay shorted Gear selector switch circuit problem no sig
40. nal Gear selector switch circuit problem invalid signal GM Powertrain Control Module PCM computer circuit problem communication interrupt failure 2 14 SERVICE CODE DEFINITION Hold mode voltage is too low Reference input intermittent Gear selector error signal Powertrain Control Module PCM computer circuit problem Hold mode stuck on Battery voltage out of range Hold mode stuck off ESC Knock present Powertrain Control Module PCM computer circuit problem 5 volt reference ground Transaxle temperature sensor failure Generic Field Effect Transistor FET driver failure Powertrain Control Module PCM Battery voltage unstable Possible open or intermittent in DIS module harness 6X Signal fault Powertrain Control Module PCM Powertrain Control Module PCM Powertrain Control Module PCM Option check sum error set if tire size and options do not compare with those stored Powertrain Control Module PCM Ignition voltage problem Clamp shorted Clamp open Handwheel sensor circuit fault Line circuit grounded or open Line circuit shorted 2nd line circuit grounded or open Cooling system high temperature 2 15 2nd line circuit shorted Cooling system low temperature GM Retrieving ECM Codes SERVICE CODE DEFINITION 3rd line circuit grounded
41. nister line to intake manifold when energized Controls flow of vapors between carburetor bowl vent and carbon canister CANP Canister Purge solenoid CATALYTIC CONVERTER Muffler like assembly placed in exhaust system that contains a catalyst to change hydrocarbons and carbon monoxide into water vapor and carbon dioxide CCC Climate Control Center CCC Computer Command Control CCC Converter Clutch Control solenoid or its circuit CCDIC Climate Control Driver Information Center CCO Converter Clutch Override output from the computer processor to the transmission CCS Coast Clutch Solenoid or its circuit CEC Computerized Emission Control CER Cold Enrichment Rod CES Clutch Engage Switch CFI Central Fuel Injection CHECK ENGINE LIGHT Dash panel light used either to aid in identification and diagnosis of a system problems or to indicate that maintenance is required 4 2 CHECK VALVE Valve that operates like a one way gate CID Cylinder Identification sensor or its circuit CKT Circuit CL Closed Loop CLC Converter Lock up Clutch CO Carbon Monoxide COC Conventional Oxidation Catalyst COMPUTER TIMING Total spark advance in degrees before top dead center CPS Crankshaft Position Sensor Provides the ECU with engine speed and crankshaft angle position CRT Cathode Ray Tube A device for displaying video signals similar to a television picture tube Similar de
42. ntent changes as compared to the oxygen content of the atmosphere The constantly changing electrical signal is used to control fuel mixture PCM Powertrain Control Module Computer that controls engine fuel ignition and emission related functions PCV Positive Crankcase Ventilation System that controls flow of crankshaft vapors into engine intake manifold where they are burned in combustion rather then being discharged into the atmosphere PFE Pressure Feedback EGR sensor or its circuit PFI Port Fuel Injection PORTED VACUUM SWITCH Temperature actuated switch that changes vacuum connections when the coolant temperature changes POT Potentiometer POWERTRAIN CONTROL MODULE Same as ECM but also controls electronically controlled automatic transmission PROM Programmable Read Only Memory PSPS Power Steering Pressure Switch Signal is used by computer to compensate for power steering loads PVS Ported Vacuum Switch PWM Pulse Width Modulation GM GM Glossary QUAD DRIVER QDM Computer chip in the PCM capable of operating four separate outputs Some have digital and some have pulse width modulated outputs RAP Retained Accessory Power RELAY Switching device operated by a low current circuit which controls opening and closing of another higher current circuit RELIEF VALVE Pressure limiting valve located in exhaust chamber of thermactor air pump Relieves part of exhaust airflow
43. or disconnect the negative battery cable to disconnect power to the vehicle s computer 3 Wait fifteen seconds for codes to be erased from the computer s memory 4 Reconnect ECM fuse or reconnect negative battery cable NOTE Once the computer s memory has been erased your vehicle may run rough for up to 40 miles while new information is being saved in the vehicle s computer If the battery cable is removed you will have to reprogram your radio clock and memory seat position ECM SERVICE CODES e Consult your vehicle s service manual for detailed meanings or definitions related to your vehicle Refer to the appropriate service codes table for your vehicle 2 5 1 GM Engine Electronic Transmission Service Codes Saturn Engine Service Codes 2 5 2 Saturn Electronic Transmission Service Codes Refer to the Diagnostic Charts and Diagnostic Aids in your vehicle s service manual to further assist in the fault isolation and elimination process 2 2 5 1 GM Engine Electronic Transmission Service Codes Saturn Engine Service Codes SERVICE CODE DEFINITION Saturn vehicles ONLY Indicates transmission service codes will be displayed next on the Shift to D2 light 1991 92 models or Temperature indicator light 1993 and later models Diagnostic mode no distributor signal to Electronic Control Module System PASS Oxygen sensor signal fault signal too low open left oxygen sensor circuit Dual sensor models
44. t your local store distributor or the Manufacturer s Service Department USA amp Canada 800 544 4124 9 00 4 00 Monday Friday PST All others 714 241 6802 9 00 4 00 Monday Friday PST FAX 714 432 7910 24 hr GM Warranty and Service GM 5 2 3123 y INN VA INNOVA ELECTRONICS CORPORATION 17287 Mt Herrmann Street Fountain Valley CA 92708 USA lnnova 1998 GM
45. thin a ten second period LEAVE THE CODE READER CONNECTED AFTER THE FOURTH TIME 3 8 8 The Service ABS light should display code 12 continuously If any other codes are displayed repeat steps 1 through 6 Turn off ignition 3 4 5 Erasing Service Codes for Bosch 2U Systems 3 5 1 Turn on ignition and observe Anti Lock light Anti Lock light should turn off within 3 to 4 seconds If Anti Lock light remains on a fault is still present NOTE Service codes cannot be erased until all stored service codes have been retrieved LEEI O TEE Set Selector Switch to ABS A H position ECM A B Connect the Code Reader to the vehicle test connector and ABS A H observe Anti Lock light CODE READER When Anti Lock light turns on disconnect Code Reader When Anti Lock light turns off reconnect Code Reader and observe Anti Lock light When Anti Lock light turns on disconnect Code Reader Repeat step 5 When Anti Lock light turns off reconnect Code Reader Anti Lock light will turn on Disconnect Code Reader All service codes are now cleared Turn off ignition Repeat procedure for retrieving service codes paragraph 3 3 4 to make sure codes have been erased ABS SERVICE CODES Consult your vehicle s service manual for detailed meaning related to your vehicle Determine your vehicle s ABS Type paragraph 3 2 and refer to the appropriate service codes table Teves II Para
46. to spark knock caused by over advanced ignition timing LEAN MIXTURE Air fuel mixture that has excessive oxygen left after all fuel in combustion chamber has burned 1 part fuel to 15 or more parts air LED Light Emitting Diode LOCK UP TORQUE CONVERTER Converter with internal mechanism that locks turbine to impeller when engaged LPA Low Pressure Accumulator LUS Lock Up Solenoid M C Mixture control or mixture control solenoid MAF Mass Air Flow sensor used to measure amount of airflow through the throttle body MAP Manifold Absolute Pressure sensor or its circuit MAT Manifold Air Temperature MFI Multi port Fuel Injection MIL Malfunction Indicator Light Check engine light MIXTURE CONTROL SOLENOID Device installed on carburetor that regulates the air fuel ratio MLP Manual shift Lever Position sensor or its circuit MPFI Multi Port Fuel Injection MULTI PORT FUEL INJECTION Individual injectors for each cylinder mounted in intake manifold Injectors are pulsed in groups rather than individually NDS Neutral Drive Switch NGS Neutral Gear Switch or its circuit NON VOLATILE MEMORY Memory retained in block learn cells not affected by turning the ignition ON or OFF NOx Nitrous Oxides NPS Neutral Pressure Switch or its circuit OCT ADJ Octane Adjust device which modifies ignition spark OXYGEN SENSOR Sensor that changes its voltage output as exhaust gas oxygen co
47. vices used on General Motors vehicles are referred to as DID or VIC CTS Coolant Temperature Sensor CURB IDLE Computer controlled idle rpm CVR Control Vacuum Regulator CWM Cold Weather Modulator CYLINDER IDENTIFICATION SIGNAL CID A signal generated by crankshaft timing sensor used to synchronize ignition coils due to the fact that some models use a 2 ignition coil pack DIS system Computer Controlled Coil Ignition Produces ignition spark without aid of an ignition distributor DCL Data Communications Link DERM Diagnostic Energy Reserve Module and air bag SIR controller DFS Decel Fuel Shut off DIC Driver Information Center DID Driver Information Display DIS Direct Ignition System Produces ignition spark without aid of an ignition distributor Similar to CSD DLC Data Link Connector DRA Digital Ratio Adapter DRAB Digital Ratio Adapter Buffer DRAC Digital Ratio Adapter Calibrator DTC Diagnostic Trouble Code GM GM Glossary DUAL CATALYTIC CONVERTER Combines 2 converters in one shell Controls NOx HC and CO Also called TWC DV TW Delay Valve 2 Way DVM 10 MEG Digital voltmeter with a minimum of 10 million ohms resistance Allows measurement in circuit without affecting the circuit operation DWELL Amount of time recorded a dwell meter degrees that current passes through a closed switch EAS Electronic Air Switchin
48. xhaust emissions AIR BPV Thermactor Air Bypass Valve AIS Automatic Idle Speed circuit and or motor ALDL Assembly Line Data Link Diagnostic connector under dash Same as ALCL AMI Thermactor Air Management AM2 Thermactor Air Management TAD AMBIENT TEMPERATURE Temperature of air surrounding vehicle being serviced ANTI BFV Anti Backfire Valve AOD Automatic Over Drive transmission ATDC After Top Dead Center AVOM Analog Volt Ohm Meter AWD All Wheel Drive AXOD Automatic Overdrive transaxle AXOD E Electronic Automatic Overdrive transaxle GM GM Glossary BAC Bypass Air Control valve BARO Barometric Pressure BASE IDLE Idle rpm determined by throttle switch with idle speed control fully retracted BCM Body Computer Module BOO Brake On Off input to the computer BOOST Turbo charger boost solenoid or its control circuit BP Barometric Pressure sensor Used to compensate for altitude variations BPMV Brake Pressure Modulator Valve BTDC Before Top Dead Center BVT Back pressure Variable Transducer CALPAC A device used with fuel injection to allow fuel delivery in the event of a PROM or PCM malfunction CANISTER A container in an evaporative emission system that contains charcoal to trap fuel vapors from the fuel system CANISTER PURGE SOLENOID Electrical solenoid or its control line Solenoid opens a valve from fuel vapor ca
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