TROUBLE CODE DEFINITION
| Code | System Affected | Probable Cause |
|---|---|---|
| 12 | System Normal | System Normal |
| 13 | Oxygen Sensor Circuit | Sensor/Circuit, ECM |
| 14 | Coolant Temperature Sensor (Shorted) | Temperature Sensor/ Circuit, ECM |
| 15 | Coolant Temperature Sensor (Open) | Temperature Sensor/ Circuit, ECM |
| 21 | Throttle Valve Switch (Idle & Full Throttle) | Switch/Circuit, ECM |
| 22 | Starter Signal | Circuit, ECM |
| 23 | Power Transistor (Shorted) | Transistor/Circuit, ECM |
| 25 | Pressure Regulator VSV | VSV/Circuit, ECM |
| 26, 27 | Canister Purge VSV | VSV/Circuit, ECM |
| 32 | EGR System | EGR Valve, Backpressure Transducer, Vacuum Switching Valve |
| 33 | Fuel Injector Circuit (Open or Grounded) | Wiring, Dropping Resistor, ECM |
| 34 | MAP Sensor | Sensor/Circuit, ECM |
| 35 (1) | Power Transistor (Open) | Transistor/Circuit, ECM |
| 41 | Crankshaft Position Sensor | Sensor/Circuit, ECM |
| 43 | Throttle Valve Switch (Idle Position) | Switch/Circuit, ECM |
| 44, 45 | Oxygen Sensor (Lean/Rich) | Injectors, Fuel Pressure, Airflow Sensor, Oxygen SensorCircuit, Coolant Temperature Sensor, ECM |
| 51 | Faulty ECM ROM | Defective ECM |
| 52 | Faulty ECM RAM | Defective ECM |
| 53 (2) | Pressure Regulator VSV | VSV/Circuit, ECM |
| 54 (1) | Power Transistor (Grounded) | Transistor/Circuit, ECM |
| 61, 62 | Airflow Sensor | Sensor/Circuit, ECM |
| 63 | Vehicle Speed Sensor | Sensor/Circuit, ECM |
| 64 | Fuel Injector Circuit (ECM Transistor) | Wiring Harness, ECM |
| 65 (3) | Throttle Valve Switch (Full Throttle) | Switch/Circuit, ECM |
| (1) See CODE 23 . (2) See CODE 25 . (3) See CODE 43 . | ||
| (1) | See CODE 23 . |
| (2) | See CODE 25 . |
| (3) | See CODE 43 . |
CODE IDENTIFICATION
Inspection & Correction
- If battery voltage is not present at terminals No. 1, 14 and 4, check main relay, starter switch, fuses, fusible link wires and related circuits. Correct or replace parts as necessary.
- If continuity does not exist between terminals No. 11 and 22, correct or replace grounding cable.
- Reconnect ECM harness connectors.
Scheme 1
TEST NO. 2 - CHECK ENGINE LIGHT INOPERATIVE
Note. Before replacing ECM, check resistance of ECM-controlled relay and solenoid coils. See appropriate WIRING DIAGRAM in WIRING DIAGRAMS section at the end of this article for coil terminal identification of solenoids and relays. Replace any solenoid or relay with less than 20 ohms resistance.
Scheme 2
Scheme 3
Scheme 4
TEST NO. 3 - WILL NOT FLASH CODE 12
Note. See appropriate WIRING DIAGRAM in WIRING DIAGRAMS section for terminal and connector identification.
Scheme 5
FUEL METERING RICH FAULTY INSPECTION PROCEDURE
Note. See appropriate WIRING DIAGRAM in WIRING DIAGRAMS section for terminal and connector identification.
Scheme 6
FUEL METERING LEAN FAULTY INSPECTION PROCEDURE
Note. See appropriate WIRING DIAGRAM in WIRING DIAGRAMS section for terminal and connector identification.
