Component Tests and General Diagnostics

CHECKING THE ECM POWER AND GROUNDS

For a complete wiring diagram refer to the Wiring Information Electrical Diagrams.






1. ECM GROUND CIRCUIT(S) OPEN
1. Turn the ignition off.
2. Disconnect the ECM harness connectors.
3. 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 the ECM VERIFICATION TEST. Powertrain Verification Test

2. FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the ECM harness connectors.
3. Turn the ignition on.
4. 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 the ECM VERIFICATION TEST. Powertrain Verification Test

3. FUSED B+ CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the ECM harness connectors.
3. 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 the ECM VERIFICATION TEST. Powertrain Verification Test

No

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