Using Check Engine Lamp

If on-board diagnostic system fails to operate, refer to "On-Board Diagnostics Failure" in this section.

1. Locate diagnostic connector at lefthand side firewall near the master cylinder.

Fig. 3 Bosch Motronic Electronic Engine Control System Terminal Identification:

2. Jumper a toggle switch between terminals 1 and 4, Fig. 3, of the four pin diagnostic connector.
3. Turn ignition switch to Run position.
4. Turn toggle switch on for 2.5 to 10 seconds, then turn the switch off.

Fig. 4 Bosch Motronic Electronic Engine Control Diagnostic Code Output:

5. After approximately 3.6 seconds the check engine lamp will flash a code 12, Fig. 4, indicating start of self-diagnosis.
6. To read the next code, turn toggle switch on for 2.5-10 seconds, then turn the switch off. This is required to access each additional code.
7. After all codes have been accessed, a code 11 will indicate end of diagnosis.
8. To restart the diagnostic code output, beginning with code 12, repeat steps 4 through 7 of this procedure. Fault codes can also be read with the engine running at less than 2000 RPM.
9. To exit diagnostics, turn ignition switch Off, then disconnect toggle switch from the diagnostic connector.
10. Note all diagnostic codes, then perform test procedures as described under "Diagnostic Code Interpretation & Testing" in this section.