GM GM 92-93 4.9L VIN B Trouble Code Info

GM

92-93 4.9L VIN B
Trouble code Fault location Probable cause
12 PCM did not receive distributor reference pulses for 4 seconds. Wiring open circuit/short circuit to ground/short circuit to positive, HEI module, HEI pick up coil, ECM
13 Oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. Engine was at normal operating temperature at a speed over 800 RPM. Wiring open circuit/short circuit to ground/short circuit to positive, O2S, ECM
14 Coolant temperature sensor signal indicates a temperature of over 313° F. Wiring short circuit to ground, ECT sensor, ECM
15 Coolant temperature sensor signal indicates a temperature colder than -27° F. Wiring open circuit, ECT sensor, ECM
16 Ignition voltage was either less than 10 volts or greater than 16 volts for 5 seconds. Wiring, alternator, ECM
17 (Eldorado & Seville) Oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. Engine was at normal operating temperature and over 800 RPM. Wiring open circuit/short circuit to ground/short circuit to positive, O2S, ECM
19 Fuel pump feedback voltage stayed above 7 volts for 4 seconds after ignition was turned on. Wiring short circuit to positive, fuel pump relay, engine oil pressure switch, ECM
20 Fuel pump feedback voltage was 2 volts or less for 1 second. Wiring open circuit/short circuit to ground/short circuit to positive, fuel pump relay, fuel pump, engine oil pressure switch, ECM
21 TPS value was 72 degrees or more for 0.7 seconds. Wiring open circuit/short circuit to positive, TP sensor, ECM
22 TPS value was 1.3 degrees or less for 0.7 seconds when the engine was running at 600 RPM or more. Wiring open circuit/short circuit to ground, TP sensor, ECM
23 EST signal did not change when the ECM applied bypass voltage to the ignition module. Wiring open circuit/short circuit to ground, HEI pick up coil, ICM, ECM
24 Vehicle speed was 0 for 3 seconds with transmission in drive or reverse and brake off when throttle angle was at least 17 degrees and engine RPM was 1400 or greater. Wiring open circuit/short circuit to ground, VSS, ECM
26 Throttle switch input to the PCM was closed for 1.8 seconds while the TPS was between 20 and 75 degrees. Wiring open circuit/short circuit to ground, TPS, ECM
27 Throttle switch was open when vehicle was coasting down with brake applied. Throttle angle was 16.5 degrees or less but RPM was greater than desired. Wiring open circuit, ISC actuator, ECM
30 TPS was 14 degrees or more while ISC was retracting for 15 seconds, or TPS was 2 degrees while ISC was extending for 15 seconds. Wiring short to ground, misfire, throttle valve tight/sticking, intake system leaking, TPS, ISC actuator, ECM
31 MAP sensor was shorted to 5 volts for 0.2 seconds. Wiring open circuit/short circuit to positive, ECM
32 MAP sensor was open showing a reading of 0.5 volts or less for 0.2 seconds. Wiring open circuit/short circuit to ground, MAP sensor, ECM
34 MAP sensor signal voltage was too high (low vacuum) for 15 seconds when throttle switch was closed. Wiring open circuit/short circuit to positive, MAP sensor, ECM
37 MAT sensor was shorted showing a temperature of 313° F or more. Wiring short circuit to ground/short circuit to positive, IAT sensor, ECM
38 MAT sensor was open showing a temperature of -27° F or less. Wiring open circuit, IAT sensor, ECM
39 Engine RPM was outside of the range expected for indicated vehicle speed indicating a VCC engagement problem. Wiring open circuit/short circuit to ground, supply wire, transmission internal wiring, TCC solenoid, transmission mechanical fault, ECM
40 Power steering switch was open when vehicle was at a speed of 45 MPH or greater. Wiring open circuit/short circuit to ground/short circuit to positive, PSP switch, ECM
41 CAM reference pulses were not received when distributor reference pulses were received at an engine speed of 1600 RPM or less. Wiring open circuit/short circuit to ground, CMP sensor, ECM
42  Left oxygen sensor was lean for more than 50 seconds when engine was warm and at 800 RPM or greater. (Eldorado & Seville only) Wiring short circuit to ground, injector(s) blocked, fuel contamination, fuel pressure low, exhaust system leaking, O2S, ECM
43 Left oxygen sensor was rich for more than 50 seconds when engine was warm and at 800 RPM or greater. (Eldorado & Seville only) Wiring open circuit/short circuit to positive, fuel pressure high, injector(s) leaking, O2S contamination, EVAP canister purge, MAP sensor hoses, O2S, ECM
44 Right oxygen sensor was lean for more than 50 seconds when engine was warm and at 800 RPM or greater. Wiring open circuit/short circuit to ground, injector(s) blocked, fuel contamination, fuel pressure low, exhaust system leaking, O2S, ECM
45 Right oxygen sensor was rich for more than 50 seconds when engine was warm and at 800 RPM or greater. Wiring open circuit/short circuit to positive, fuel pressure high, injector(s) leaking, O2S contamination, EVAP canister purge valve, MAP sensor hoses, O2S, ECM
46 Left and right fuel control block learn values differ by more than 15 counts for 10 minutes. (Eldorado & Seville only) Injector(s) leaking, HO2S, intake/exhaust system leaking, spark plug(s), ignition system
47 PCM has received bad data from IPC for 3 seconds while engine speed was 500 RPM or more for 3 seconds. Wiring, BCM
48 EGR open command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. Vehicle speed was over 35 MPH and engine was warm. Wiring open circuit/short circuit to ground, supply wire, vacuum hoses, EGR solenoid, ECM
51 (Eldorado & Seville) MEM-CAL error. Insecure PROM, incorrect PROM, ECM
52 PCM has lost primary battery power. Battery disconnected, ECM disconnected
53 Distributor reference pulses were not received for 0.4 seconds when engine speed was greater than 568 RPM. Wiring open circuit/short circuit to positive, HEI module pick up coil
55 TPS zero point was out of range. Throttle valve tight/sticking, ISC actuator, TP sensor, TP sensor incorrectly adjusted
58 Pass Key fuel enable was not correct. Incorrect ignition key, wiring open circuit/short circuit to ground/short circuit to positive, immobilizer control module, ECM
60 Transmission was not in drive when cruise control was engaged. Driver error, wiring open circuit/short circuit to ground, PNP switch
61 Cruise vent solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. Wiring open circuit/short circuit to ground/short circuit to positive, cruise control servo, ECM
62 Cruise vacuum solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. Wiring open circuit/short circuit to positive, cruise control servo, ECM
63 Cruise control servo position was at least 39% with cruise engaged. Vehicle speed was 20 MPH higher than the set speed for 0.5 seconds. Wiring short circuit to positive, hoses leaking, cruise control servo, throttle binding
64 Vehicle speed increased more than 16 MPH in 1 second while cruise control was engaged. Slippery road conditions
65 Cruise control servo position was 6.3% or less for 1 second. Wiring open circuit/short circuit to ground, cruise control servo
66 Engine RPM was 4800 or more for 0.25 seconds with cruise control engaged. Slippery road conditions, transmission mechanical fault
67 Cruise control Set/Coast or Resume/Accel switch was closed for 10 minutes. Wiring short circuit to ground/short circuit to positive, supply wire, cruise control switch, ECM
68 With cruise control engaged the throttle angle was greater than 20 degrees and servo position sensor indicated a stroke greater than commanded. Wiring short to positive, hoses blocked/leaking, brake pedal vacuum valve, cruise control servo, throttle binding
70 Throttle position changed too rapidly without a corresponding change in MAP sensor signal when engine was running. Wiring open circuit/short circuit to ground/short circuit to positive, TP sensor, throttle binding
71 MAP sensor signal changed too rapidly while TPS signal was steady and engine speed did not change. Wiring open circuit/short circuit to ground/short circuit to positive, MAP sensor
73 Coolant temperature sensor voltage has changed 0.3 volts in 1 second. Wiring open circuit/short circuit to ground/short circuit to positive, ECT sensor
74 MAT sensor signal changed 7 degrees or more in 0.25 seconds. Wiring open circuit/short circuit to ground/short circuit to positive, IAT sensor
75 Vehicle speed changed by 8 MPH or more in 1 second while MAP sensor remained steady with engine running and brakes not applied. Wiring open circuit/short circuit to ground/short circuit to positive, VSS
80 Block learn was 104 or less for 25 seconds with a throttle angle between 6 and 30 degrees and engine was warm. Fuel pressure high, injector(s) leaking, EVAP system
85 The coast down throttle angle offset is more than 5 degrees from the zero value. Throttle valve tight/sticking, TP sensor, ISC actuator
90 Vehicle speed cycles from 30 MPH to 0 at least 10 consecutive times with no VCC brake switch input. Wiring open circuit/short circuit to positive, incorrectly adjusted BPP switch, BPP switch, ECM
91 Gear selector switch has either an open or a short causing an invalid signal for a forward or reverse gear. Wiring open circuit/short circuit to ground, incorrectly adjusted PNP switch, PNP switch, ECM
92 Heated window signal was present at PCM for 10 minutes or more. Wiring open circuit/short circuit to ground/short circuit to positive, console switch, windshield control module
96 Throttle angle was 65 degrees or more for 12 seconds with transmission in drive or reverse and vehicle speed was 5 MPH or less with brake being applied. ECM trouble codes stored, driver error
97 Gear selector was moved from park or neutral to drive or reverse with engine speed over 2000 RPM but under 6 MPH. Driver error, wiring, transmission range (TR) switch
98 At a vehicle speed under 6 MPH, the gear selector was moved from park or neutral into drive or reverse when engine speed was 600 RPM greater than determined by PCM. Driver error, wiring, transmission range (TR) switch
99 Servo position sensor indicated that servo was still engaged after cruise control had been disengaged for 2 seconds. Throttle angle was above 20 degrees. Wiring short to positive, throttle valve tight/sticking, hoses blocked/leaking, cruise control servo