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Glossary

GM

4-8

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 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.

SEFI, 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.

Summary of Contents for GM 3123

Page 1: ......

Page 2: ...RKSHEET RETRIEVING ECM CODES 2 1 VEHICLES COVERED 2 1 2 2 BEFORE YOU BEGIN 2 2 2 3 RETRIEVING SERVICE CODES 2 3 2 4 ERASING SERVICE CODES 2 6 2 5 ECM SERVICE CODES 2 6 RETRIEVING ABS CODES 3 1 ANTI LO...

Page 3: ...e b l o w n f u e l i n j e c t o r f u s e I g n i t i o n s y s t e m f a u l t I n t e r m i t t e n t 7 X s i g n l o s s o f 5 8 X s i g n a l o r 6 X s i g n a l S a t u r n 1 T h r o t t l e p...

Page 4: ...fore you can obtain service codes from the vehicle s onboard computer 1 1 2 Service Codes The service codes are also called fault codes diagnostic codes or trouble codes These codes can be used to ide...

Page 5: ...ontrols and Indicators Selector Switch Selects operating mode for Code Reader ECM A B Use to retrieve ECM codes ABS A H Use to retrieve ABS service codes 1 3 TEST CONNECTOR LOCATIONS The gateway to yo...

Page 6: ...ice man uals before any test or tune up procedures are performed IMPORTANT You MUST use the wiring diagrams in your vehicle s service manual to ensure proper connections during testing Contact your lo...

Page 7: ...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 cl...

Page 8: ...long time No symptoms Right after starting When shifting into gear During steady speed driving Right after vehicle comes to a stop While idling During acceleration When parking No symptoms Is too slow...

Page 9: ...gear engagement With A C operating With headlights on During acceleration Mostly driving downhill Mostly driving uphill Mostly driving level Mostly driving curvy roads Mostly driving rough roads Most...

Page 10: ...orvette 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 Ni...

Page 11: ...h some of these systems see paragraph 2 1 16 Pin Connector The new 16 pin connector was introduced on some 1994 and 1995 models and was made standard equipment on all 1996 and subsequent model year ve...

Page 12: ...own mechanical problems before this test Have pencil and paper handy 1 Turn off ignition 2 Connect the Code Reader to the vehicle test connector NOTE The Code Reader only fits into the connector one w...

Page 13: ...the vehicle s computer Consult your vehicle s repair manual for no codes problems Code 22 looks like IMPORTANT Any code that ends in zero 0 is transmitted as follows Code 30 looks like 6 Next erase s...

Page 14: ...ing Fault Codes Diagnostic trouble codes indicate a problem in a circuit not necessarily a faulty component DO NOT replace components based only on trouble codes without first following the service pr...

Page 15: ...connect 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 batte...

Page 16: ...ect ignition system DIS fault line open or shorted to ground Ignition system fault loss of 2X or Low Resolution Pulse signal Transmission speed error 17 RPM signal problem Camshaft sensor circuit prob...

Page 17: ...pressure switch assembly open or short circuit problems 29 4th gear switch Quad Driver module or Quad driver No 3 error Secondary air injection system circuit problems 31 Manifold absolute pressure MA...

Page 18: ...low 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 electr...

Page 19: ...uter 48 Misfire symptom Mass air flow MAF sensor circuit error 49 RPM is high at idle possible vacuum leak 50 System voltage is low 51 Computer problem faulty wrong or incorrectly installed PROM circu...

Page 20: ...R 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 64 EGR flow problem or on board cruise c...

Page 21: ...VSS loss of signal 73 Air conditioning evaporator temperature sensor circuit fault high temp Transmission Pressure control solenoid circuit problems 74 Traction control circuit voltage low 75 Digital...

Page 22: ...ule ECM error or shift Solenoid B stuck on 87 Electrically Erasable Programmable Read Only Memory EEPROM error or shift Solenoid B stuck off or high gear ratio error 88 Electronic Control Module ECM c...

Page 23: ...ars available 21 2nd gear stuck on 22 No 2nd gear 23 No 3rd gear 24 No 4th gear 25 No torque converter clutch 26 Torque converter clutch stuck on 27 Quick quad driver output fault 31 Transaxle tempera...

Page 24: ...ET driver failure 57 Powertrain Control Module PCM 58 Battery voltage unstable 61 Possible open or intermittent in DIS module harness 6X Signal fault Powertrain Control Module PCM 62 Powertrain Contro...

Page 25: ...tch TCC circuit shorted 82 Transaxle temperature unstable 83 Transaxle temperature low Low coolant 84 Brake switch stuck open 85 Brake switch stuck closed 86 Engine speed invalid 87 Torque Converter C...

Page 26: ...ral 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...

Page 27: ...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 Sabr...

Page 28: ...retesting after each repair is made to be sure the fault was eliminated 3 3 1 Retrieving Service Codes for Teves II Systems 1 Turn on ignition DO NOT START THE ENGINE Observe Anti Lock light If Anti L...

Page 29: ...es 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 1 Turn off ignition 2...

Page 30: ...ce 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 Co...

Page 31: ...ument 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 g...

Page 32: ...been erased and no new codes have been recorded 3 4 2 Erasing Service Codes for Kelsey Hayes RWAL Systems A For all vehicle models EXCEPT C and K 3500 Series Heavy Duty HD 1992 93 1 Turn off ignition...

Page 33: ...or one second reconnect the Code Reader for two seconds then remove the Code Reader 4 The Anti Lock and Brake light should BOTH light then turn off This indicates service codes have been erased 5 Turn...

Page 34: ...urns on disconnect Code Reader 5 When Anti Lock light turns off reconnect Code Reader and observe Anti Lock light When Anti Lock light turns on disconnect Code Reader 6 Repeat step 5 7 When Anti Lock...

Page 35: ...33 Right rear Wheel Speed Sensor 34 Left rear Wheel Speed Sensor 35 Left front Wheel Speed Sensor 36 Right front Wheel Speed Sensor 37 Right rear Wheel Speed Sensor 38 Left rear Wheel Speed Sensor 41...

Page 36: ...mp valve or faulty ECU 4 Grounded anti lock valve reset switch circuit 5 Excessive actuation of the dump valve during an anti lock stop 6 Erratic speed signal 7 Shorted isolation valve circuit or faul...

Page 37: ...peed sensor fault or VSS circuit open 1993 36 Missing left rear speed signal or VSS signal missing 1993 37 Erratic left rear speed signal or erratic VSS signal 1993 38 Wheel speed error 41 4 Wheel Ant...

Page 38: ...WAL control unit fault 67 Open motor circuit or shorted ECU output 68 Locked motor or shorted motor circuit 71 4 Wheel Anti Lock 4WAL control unit fault 72 4 Wheel Anti Lock 4WAL control unit fault 73...

Page 39: ...r open circuit 76 Lateral accelerometer fault signal out of range or incorrect Code Service Code Definition 12 Normal 21 Right front wheel sensor fault 22 Right front toothed wheel frequency error 25...

Page 40: ...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 Con...

Page 41: ...or its control line Solenoid opens a valve from fuel vapor canister line to intake manifold when energized Controls flow of vapors between carburetor bowl vent and carbon canister CANP Canister Purge...

Page 42: ...mputer 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...

Page 43: ...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 Reci...

Page 44: ...ECIRCULATION 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 compute...

Page 45: ...ice 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 paramet...

Page 46: ...haust gas oxygen content 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 th...

Page 47: ...light SEFI 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 Ligh...

Page 48: ...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 Tu...

Page 49: ...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...

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