GM Import / GEO – TroubleCodes.net

Table of Contents

NOTE: 96 & later are OBD2 systems and require a scanner. For an OBD2 code list, please see our GM code list or the appropriate generic list.

GM Import Codes by Model

Model	Year	Engine identification	System
Geo 1.6L	90	–	–
Geo 1.6L	91	–	–
Geo 1.6L	95	–	–
Prizm 1.6L	1992-97	VIN position 8 =6	TCCS
Prizm 1.8L	1992-97	VIN position 8 =8	TCCS
Tracker 1.6L	1992-97	G16	EPI

87-88 Sprint Turbo,89 & later Metro, Tracker, Storm.
12	Diagnostic function working
13	Oxygen sensor or circuit
14	Coolant temperature sensor or circuit (open)
15	Coolant temperature sensor or circuit (shorted)
21	Throttle position sensor or circuit (open)
22	Throttle position sensor or circuit (shorted)
23	Intake air temperature sensor or circuit (open)
24	Vehicle speed sensor (VSS) or circuit
25	Intake air temperature sensor or circuit (shorted)
31	High turbo pressure (87 – 88)
31	Barometric pressure sensor or circuit (89 -95)
32	Barometric pressure sensor or circuit (89 – 95)
32	EGR system (91 – 93)
33	Airflow meter (turbo)
33	Manifold Absolute Pressure (MAP) sensor (90 – 91)
41	Ignition signal problem
42	Crank angle sensor (except Storm)
42	Camshaft position sensor circuit (94-95)
42	Electronic Spark Timing (EST) (Storm)
44	ECM idle switch circuit open
44	Oxygen sensor or circuit – lean exhaust
45	Oxygen sensor or circuit – rich exhaust
46	Idle speed control motor
51	EGR system (except Storm)
51	ECM (Storm)
53	ECM ground circuit
ON Steady	ECM faulty

89 – 92 GEO Metro TBI
13	Oxygen Sensor circuit.
14	Coolant Temperature Sensor circuit. High temperature indicated.
15	Coolant Temperature Sensor circuit. Low temperature indicated.
21	Throttle Switch circuit (Manual Transmission).
21	Throttle Position Sensor Signal Voltage High (Automatic Transmission).
22	Throttle Position Sensor Signal Voltage Low.
23	Intake Air temperature (MAT) Sensor. Low temperature indicated.
24	Vehicle Speed Sensor circuit.
25	Intake Air temperature (MAT) Sensor. High temperature indicated.
31	MAP Sensor circuit – Signal Voltage Low Vacuum.
32	MAP Sensor circuit – Signal Voltage High Vacuum.
33	MAP Sensor circuit.
41	Ignition Signal circuit.
42	Crank Angle Sensor.
46	Idle Speed Control Motor circuit.
51	EGR circuit.
53	Ground circuit.

93 – 95
13	Oxygen Sensor circuit. Signal voltage does not change.
14	Engine Coolant Temperature Sensor circuit High Voltage Input. Low temperature indicated.
15	Engine Coolant Temperature Sensor circuit Low Voltage Input. High temperature indicated.
21	Throttle Position Sensor circuit High Voltage Input.
22	Throttle Position Sensor circuit Low Voltage Input.
23	Intake Air temperature Sensor circuit – High Voltage Input. Low temperature indicated.
24	Vehicle Speed Sensor circuit.
25	Intake Air temperature Sensor circuit – Low Voltage Input. High temperature indicated.
31	MAP Sensor circuit Low Voltage Input – Low manifold pressure.
32	MAP Sensor circuit High Voltage Input – High manifold pressure.
41	Ignition Signal circuit.
42	Crankshaft Position Sensor circuit – No Signal for 2 seconds.
46	Idle Speed Control Motor circuit.
51	EGR circuit.

Sprint(non-turbo)
12	Diagnostic function working
13	Oxygen sensor circuit
14	Coolant temperature sensor circuit
21	Throttle position switches or circuit
23	Intake air temperature circuit
32	Barometric Pressure circuit
51	Possible faulty ECM
52	Fuel cut solenoid or circuit
53	Secondary air circuit
54	Mixture control solenoid or circuit
55	Bowl vent solenoid or circuit

GEO, Sprint, Nova & Spectrum
12	No distributor reference pulse to ECM
13	Oxygen sensor circuit
14	Coolant sensor – high or low temp
21	Throttle Position Sensor (TPS) voltage high or low
23	Intake Air Temperature IAT sensor circuit voltage high or low
24	Vehicle Speed Sensor (VSS) or circuit
32	EGR (Exhaust gas recirculation) EVRV shorted to ground on start-up
33	Manifold Absolute Pressure (MAP) sensor voltage high or low
42	Electronic Spark Timing (EST) circuit
43	Detonation (knock) sensor or circuit–Turbo type
44	Oxygen sensor or circuit indicates lean exhaust (heated type)
45	Oxygen sensor or circuit indicates rich exhaust
51	ECM or EEPROM

Spectrum
12	No distributor reference pulses to ECM
13	Oxygen sensor circuit
14	Coolant sensor circuit shorted.
15	Coolant sensor circuit open.
16	Coolant sensor circuit open.
21	Idle switch out of adjustment (or open circuit) non-Turbo t
21	Throttle Position Sensor (TPS) voltage high– Turbo
22	Fuel cut off relay or circuit open–non-Turbo
22	Throttle Position Sensor (TPS) voltage low–Turbo
23	Open or grounded Mixture Control(M/C) solenoid or circuit– non-Turbo
23	Manifold Air Temperature MAT sensor or circuit–Turbo
24	Vehicle Speed Sensor (VSS) or circuit–Turbo
25	Open or grounded vacuum switching valve or circuit–non-Turbo
25	Air Switching Valve (ASV) or circuit–Turbo
31	Wastegate control–Turbo
33	Manifold Absolute Pressure (MAP) sensor voltage high–Turbo
34	Manifold Absolute Pressure (MAP) sensor voltage low–Turbo
42	Electronic Spark Timing (EST) circuit EST circuit is grounded or open. Turbo
42	Fuel cut off relay or circuit non-Turbo type
43	Detonation (knock) sensor or circuit–Turbo type
44	Oxygen sensor or circuit indicates lean exhaust non-Turbo
45	Oxygen sensor or circuit indicates rich exhaust
51	ECM or PROM
53	Shorted switching unit or faulty ECM non-Turbo
54	Mixture Control (M/C) solenoid or circuit, or faulty ECM non-Turbo
55	Faulty ECM non-Turbo