Component Tests and General Diagnostics

CHECKING THE ECM POWER AND GROUNDS

For a complete wiring diagram, refer to the Wiring Information .






1. PCM GROUND CIRCUIT(S) OPEN
1. Turn the ignition off.
2. Disconnect the PCM harness connectors.
3. Using a 12-Volt test light connected to 12-Volts, check each of the PCM ground circuits in PCM harness connector.

Did the test light illuminate for each cavity?

Yes

- Go To 2

No

- Repair the PCM Ground circuit(s) for an open.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

2. FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the PCM 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 PCM harness connector.

Is the test light on?

Yes

- Go To 3

No

- Repair the Fused Ignition Switch Output circuit for an open.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. FUSED B+ CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the PCM harness connectors.
3. Using a 12-Volt test light connected to ground, check each Fused B+ circuit in the PCM harness connector.

Does the test light illuminate brightly for each circuit?

Yes

- Test Complete.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Repair the Fused B+ Output circuit for an open.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.