Chart A-4 Injector Circuit Diagnosis

Chart A-4 Injector Circuit Diagnosis:

Injector Circuit:

Circuit Description:
This chart should only be used if diagnosis in CHART A-3 indicated an injector circuit problem. Related Tests, Information and Procedures

Chart Test Description
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test checks for ignition voltage at the injector jumper harness connector.

2. Checks for open in CKT 467 or 468 from PCM to injector jumper harness connector. The test light has a path to voltage through the injector windings to ignition CKT 439.

3. Checks for short to voltage on CKT 467 or 468 from PCM to injectors. Be sure injector jumper harness connector is disconnected.

4. Damage to the PCM injector driver may occur if injector driver CKT 467 or 468 shorts to ignition CKT 439.

Diagnostic Aids
The PCM has integrated circuits that are fault protected, therefore, if a circuit has failed, the integrated circuits may not be damaged and will keep the circuit open until the fault in the circuits has been corrected. When the fault has been corrected, reinstall PCM and check circuit. Replace PCM only if the circuit is still inoperative.