Checking the ECM Power and Ground Circuits

*CHECKING THE ECM POWER AND GROUNDS

For complete wiring diagrams refer to Diagrams/Electrical.





Diagnostic Test


1. ECM GROUND CIRCUIT(S) OPEN

Turn the ignition off.

Disconnect the ECM harness connectors.

Using a 12-volt test light connected to 12-volts, check each of the ECM ground circuits in ECM harness connector.

Did the test light illuminate for each cavity?

Yes

- Go To 2

No

- Repair the ECM Ground circuit(s) for an open.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN

Turn the ignition off.

Disconnect the ECM harness connectors.

Turn the ignition on.

Using a 12-volt test light connected to ground, check the Fused Ignition Switch Output circuit in ECM harness connector.

Is the test light on?

Yes

- Go To 3

No

- Repair the Fused Ignition Switch Output circuit for an open.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. FUSED B+ CIRCUIT OPEN

Turn the ignition off.

Disconnect the ECM harness connectors.

Using a 12-volt test light connected to ground, check each Fused B+ circuit in the ECM harness connector.

Does the test light illuminate brightly for each circuit?

Yes

- Test Complete.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Repair the Fused B+ Output circuit for an open.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test