Chart A-4 Injector Circuit Diagnosis

Chart A-4 Central MFI Injector Circuit Diagnosis:

Ignition Circuit:

CIRCUIT DESCRIPTION
This chart should only be used if diagnosis using Chart A-3 indicated a Central Multiport Fuel Injector (CMFI) circuit problem.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart:

1. This test will determine if the ignition module is generating a reference pulse, if the wiring is at fault or if the Powertrain Control Module (PCM) is at fault. By touching and removing a test light, connected to 12 volts, to CKT 430, a reference pulse should be generated. If injector test light blinks, the PCM and wiring are OK.
2. This step tests for 12 volts to the injector. It will also determine if there is a short to voltage on the PCM side of the circuit.
3. This test checks for continuity to the PCM.

DIAGNOSTIC AIDS
The PCM has Integrated Circuits (ICs) that are fault protected, therefore, if a circuit has failed, the IC may not be damaged and will keep the circuit open until the fault has been corrected. When the fault has been corrected, reinstall PCM and check circuit. Replace PCM only if the circuit is still inoperative.