Various Models |
Trouble Code |
Fault Location |
Probable Cause |
12 |
Start of diagnosis |
No engine speed (RPM) signal received |
13 |
Oxygen sensor (02S)/heated oxygen sensor (H02S) |
Wiring open circuit, 02S/H02S, ECM |
14 |
Engine coolant temperature (ECT) sensor -voltage high/low |
Wiring, ECT sensor, ECM |
15 |
Engine coolant temperature (ECT) sensor -voltage high |
Wiring open circuit, ECT sensor, ECM |
16 |
Vehicle speed sensor (VSS) -no signal |
Wiring, VSS, ECM |
21 |
Throttle position (TP) sensor -voltage high/ low |
Wiring, 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 -voltage high |
Wiring, IAT sensor, ECM |
24 |
Vehicle speed sensor (VSS) -no signal |
Wiring, VSS, ECM |
25 |
Intake air temperature (IAT) sensor -voltage low |
Wiring short circuit to ground, IAT sensor, ECM |
26 |
Engine control module (ECM), quad driver/ output driver -circuit malfunction |
Wiring, ECM controlled components, ECM * (see below for additional information) |
27 |
Engine control module (ECM), quad driver/ output driver -circuit malfunction |
Wiring, ECM controlled components, ECM * (see below for additional information) |
28 |
Transmission gear pressure switch, signal -circuit malfunction |
Wiring open circuit/short circuit to ground, reverse/D1/D2/D3/D4 gear pressure switch(es), ECM |
31 |
Throttle control system -malfunction |
Wiring, throttle control motor, throttle control module, ECM |
32 |
Exhaust gas recirculation (EGR) solenoid |
Wiring, poor connections, EGR valve, ECM |
33 |
Manifold absolute pressure (MAP) sensor -voltage high |
Wiring, hose blocked/leaking, MAP sensor, ECM |
34 |
Manifold absolute pressure (MAP) sensor -voltage low |
Wiring open circuit/short circuit to ground, MAP sensor, ECM |
35 |
Idle air control (lAC) valve |
Wiring, lAC valve, intake system leaking, fuel system, PCV valve, 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) -stuck ON |
Wiring, BPP switch, ECM |
38 (1994-1995) |
Brake pedal position (BPP) switch, torque converter clutch (TCC) -stuck OFF |
Wiring, BPP switch, ECM |
38 (1992-1993) |
Knock sensor (KS) -circuit malfunction |
Wiring open circuit, KS, ECM |
39 (1992-1993) |
Knock sensor (KS) -circuit malfunction |
Wiring short circuit, KS, ECM |
39 (Automatic transmission 4L80E 1994) |
Brake pedal position (BPP) switch -stuck OFF |
Wiring, BPP switch, ECM |
41 |
Crankshaft position (CKP) sensor, 1X reference signal -circuit malfunction |
Wiring, ICM, ECM |
42 |
Ignition control, bypass/timing signal -circuit malfunction |
Wiring, poor connections, ICM, ECM |
43 |
Knock sensor (KS)/knock control module -circuit malfunction |
Wiring, KS, knock control module, ECM |
44 |
Oxygen sensor (02S)/heated oxygen sensor (H02S) -mixture lean |
Wiring open circuit/short circuit to ground injector(s) blocked, fuel contamination, pressure low, exhaust system leaking, 02S/ H02S, ECM |
45 |
Oxygen sensor (02S)/heated oxygen sensor (H02S) -mixture rich |
Wiring open circuit, fuel pressure high, injector(s) leaking, 02S/H02S, EVAP purge valve, TP sensor, EGR system, ECM |
51 |
Engine control module (ECM), PROM malfunction |
Poor connections, incorrect programming : ECM |
52 (1992-1993) |
Engine control module (ECM) -malfunction |
ECM, poor connections |
52 (1994-1995) |
System voltage -high |
Alternator, jump started |
53 |
System voltage -high |
Alternator, jump started |
54 |
Fuel pump circuit -voltage low |
Wiring open circuit/short circuit to ground fuel pump relay, engine oil pressure warning lamp/fuel pump switch |
55 |
Engine control module (ECM) -malfunction |
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 |
66 |
Transmission 3rd-2nd control solenoid circuit malfunction |
Wiring, control solenoid, ECM |
67 |
Torque converter clutch (TCC) solenoid 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 |
72 |
Vehicle speed sensor (VSS) -loss of signal |
Wiring, 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 |
79 |
Transmission fluid temperature (TFT) -high |
Transmission mechanical fault, tOWing weight limit exceeded |
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, ECM |
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 -higher than expected |
Wiring, input shaft speed sensor, output shaft speed sensor, mechanical fault |