Engine Controls - Basic Testing: Overview GMC Vandura P3500

Test Description

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

Scheme 175

Scheme 176

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

Scheme 177

Scheme 178

1. This test will determine if the ignition module is generating a reference pulse, if the wiring is at fault or if the ECM is at fault. By touching and removing a test light, connected to 12 volts, to circuit 430, a reference pulse sould be generated. If injector test light blinks, the ECM 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 ECM side of the circuit.
3. This test checks for continuity to the ECM. For circuit schematic see scheme 16

Scheme 179

See also:
• WIRING DIAGRAMS