Checking the ECM Power and Ground Circuits

*CHECKING THE ECM POWER AND GROUNDS

For a complete wiring diagram 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 - 6.7L. 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 - 6.7L. 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 - 6.7L. Powertrain Verification Test


No


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