GM OBD/OBD2 Codes >> GM 93-95 Chevy Van

GM

93-95 4.3, 5.0, 5.7, 7.4L VIN Z, H, K, N
Flash Code Fault Location Probable Cause
12 Start of diagnosis No engine speed (RPM) signal received
13 Oxygen sensor (O2S)/heated oxygen sensor (HO2S) Wiring open circuit, O2S/HO2S, ECM
14 Engine coolant temperature (ECT) sensor – high temperature indicated Wiring short circuit to ground, ECT sensor, ECM
15 Engine coolant temperature (ECT) sensor – low temperature indicated Wiring open circuit, ECT sensor, ECM
16  Vehicle speed sensor (VSS) buffer – signal low Wiring, VSS buffer, ECM
17  Camshaft position (CMP) sensor – circuit malfunction Wiring, CMP sensor, mechanical fault, ECM
21 Throttle position (TP) sensor – voltage high Wiring open circuit/short circuit to positive, TP sensor, ECM
22 Throttle position (TP) sensor – voltage low Wiring open circuit/short circuit to ground, TP sensor, ECM
23 Intake air temperature (IAT) sensor – low temperature Wiring open circuit, IAT sensor, ECM
24 Vehicle speed sensor (VSS) Wiring open circuit/short circuit to ground, PROM, VSS, ECM
25 Intake air temperature (IAT) sensor – high temperature Wiring short circuit to ground, IAT sensor, ECM
28                Transmission range (TR) switch Wiring open circuit/short circuit to ground/short circuit to positive, TR switch, ECM
31  Engine speed control system – malfunction Wiring, throttle valve motor, throttle valve control module, ECM
32 Exhaust gas recirculation (EGR) solenoid Wiring open circuit/short circuit to ground, EGR valve, ECM
33 Manifold absolute pressure (MAP) sensor – circuit malfunction Wiring open circuit/short circuit to positive, hose blocked/leaking, MAP sensor, ECM
34 Manifold absolute pressure (MAP) sensor – circuit malfunction Wiring open circuit/short circuit to ground, MAP sensor, ECM
35  Idle air control (IAC) valve Wiring, IAC valve, intake system leaking, fuel system, PCV valve, A/C system, mechanical fault, ECM
36 Auxiliary idle air control valve Wiring, idle air control valve, vacuum pipes, ECM
37 Brake pedal position (BPP) switch for torque converter clutch (TCC) Wiring open circuit/short circuit to ground, incorrectly adjusted BPP switch, BPP switch, ECM
38 Brake pedal position (BPP) switch/ torque converter clutch (TCC) Wiring open circuit/short circuit to ground, supply wire, BPP switch, TCC switch, ECM
39  Brake pedal position (BPP) switch – stuck OFF Wiring, BPP switch, ECM
42 Ignition control module (ICM) – electronic spark timing (EST)/ignition control (IC)/bypass circuit malfunction Wiring open circuit/short circuit to ground, ICM, ECM
43 Knock sensor (KS) Wiring open circuit/short circuit to ground/short to positive, KS, PROM, ECM
44 Oxygen sensor (O2S)/heated oxygen sensor (HO2S) – mixture lean Wiring short circuit to ground, fuel pressure low, MAP sensor, misfire, fuel contamination, exhaust system leaking, O2S/HO2S, ECM
45 Oxygen sensor (O2S)/heated oxygen sensor (HO2S) – mixture rich Fuel pressure high, injector(s) leaking, O2S contamination, EVAP canister purge valve, TP sensor, MAP sensor, EGR system, O2S/H2OS, ECM
46  Immobilizer system, code – malfunction Incorrect key, ECM
51 Engine control module (ECM) – PROM Insecure PROM, incorrect PROM, ECM
52  System Voltage – high Alternator, jump started
53  System Voltage – high Alternator
54 Fuel pump circuit – voltage low Wiring open circuit/short circuit to ground, fuel pump relay, fuel pump, engine oil pressure warning lamp switch, ECM
55  Engine control module (ECM) Ground wiring open circuit, insecure PROM, ECM
58  Transmission fluid temperature (TFT) sensor – voltage low Wiring short circuit to ground, TFT sensor, ECM
59 Transmission fluid temperature (TFT) sensor -voltage high Wiring open circuit, TFT sensor, ECM
61  Oxygen sensor (O2S) O2S
62  Transmission gear switch signal circuit Wiring open circuit/short circuit to ground, 2nd gear switch, 3rd gear switch, ECM
66 Transmission shift solenoid (SS), 3rd-2nd – downshift malfunction Wiring, SS, ECM
67 Torque converter clutch (TCC) – circuit malfunction Wiring, TCC solenoid, ECM
68  Torque converter clutch (TCC) – slipping Wiring, TCC solenoid, transmission mechanical fault, ECM
69  Torque converter clutch (TCC) solenoid – stuck ON Wiring open circuit/short circuit to ground, transmission internal wiring, TCC solenoid, transmission mechanical fault, ECM
70 A/C refrigerant pressure sensor – voltage high Wiring open circuit/short circuit to positive, A/C refrigerant pressure sensor, ECM
72 Vehicle Speed Sensor (VSS) Wiring open circuit/short circuit to ground, VSS, ECM
73  Transmission fluid pressure (TFP) control solenoid – circuit malfunction Wiring, poor connection, TFP solenoid
74  Transmission input shaft speed sensor – circuit malfunction Wiring, input shaft speed sensor, ECM
75 System voltage, engine control module (ECM) – low Wiring, battery, alternator, ECM
76 Exhaust gas recirculation (EGR) valve solenoid 2 Wiring open circuit/short circuit to ground, supply wire, EGR valve, ECM
77 Exhaust gas recirculation (EGR) valve solenoid 3 Wiring open circuit/short circuit to ground, supply wire, EGR valve, ECM
79 Transmission fluid temperature (TFT) – high Transmission mechanical fault, towing
80 Torque converter clutch (TCC) – slipping Wiring open circuit/short circuit to ground, supply wire, transmission internal wiring, TCC solenoid, transmission mechanical fault, ECM
81  Transmission shift solenoid (SS), 2nd-3rd – circuit malfunction Wiring, SS, ECM
82  Transmission shift solenoid (SS), 1st-2nd – circuit malfunction Wiring, SS, ECM
83  Torque converter clutch (TCC) solenoid, pulse width modulated – circuit malfunction Wiring, TCC solenoid, ECUM
85  Transmission input/output shaft speed, ratio variation – out of range Wiring, input shaft speed sensor, output shaft speed sensor, mechanical fault
86  Transmission input/output shaft speed, ratio variation – lower than expected Wiring, input shaft speed sensor, output shaft speed sensor, mechanical fault
87  Transmission input/output shaft speed, ratio variation – out of range Wiring, input shaft speed sensor, output shaft speed sensor, mechanical fault
90 Torque converter clutch (TCC) – stuck ON Wiring open circuit/short circuit to ground, transmission internal wiring, TCC solenoid, transmission mechanical fault, ECM
96 Engine control module (ECM) – ignition supply voltage low Wiring open circuit, alternator, ECM
98 Engine control module (ECM) – incorrectly coded ECM incorrectly coded, ECM
99  Engine control module (ECM) – incorrectly coded ECM incorrectly coded, ECM
 

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