Retrieving Codes
- Ensure ignition switch is in the OFF position. Using a jumper wire, jumper Assembly Line Diagnostic Link (ALDL) connector diagnostic test terminals No. 1 and No. 3. See Fig 1 . Connector is located behind kick panel in the passenger compartment. Turn ignition switch to ON position. Read trouble code(s). Proceed to CODE CHARTS for diagnosing stored codes.
- If no trouble codes are stored, CHECK ENGINE light will flash rapidly on then off until jumper is disconnected. Count the number of flashes and look for pauses in flashing to ensure no trouble codes are overlooked. If trouble codes are stored, code will flash 3 times and the lowest code will be given first.
TROUBLE CODE IDENTIFICATION CHART
| Code | Circuit Affected | Probable Cause |
|---|---|---|
| 13 | Oxygen Sensor | Open/Grounded Circuit |
| 4A | Coolant Temp. Sensor | High Temp. Indicated |
| 14B | Coolant Temp. Sensor | Low Temp. Indicated |
| 21A | Throttle Position Sensor | Signal Voltage High |
| 21B | Throttle Position Sensor | Signal Voltage Low |
| 23A | Manifold Air Temp. Sensor | Low Temp. Indicated |
| 23B | Manifold Air Temp. Sensor | High Temp. Indicated |
| 24 | Vehicle Speed Sensor | Incorrect Signal Voltage |
| 33A | MAP Sensor | Signal Voltage High Low Vacuum |
| 33B | MAP Sensor | Signal Voltage Low High Vacuum |
| 42 | Electronic Spark Timing | Open/Shorted Circuit |
| 44 | Oxygen Sensor | Lean Exhaust Indicated |
| 45 | Oxygen Sensor | Rich Exhaust Indicated |
| 51 | ECM Failure | ECM Failed Or EE PROM Failure |