Checking Powertrain Control Module Power & Ground Circuits (4.7L)
WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes
- PCM Fused B+ Circuit
- PCM Fused Ignition Switch Output Circuit
- PCM Ground Circuits
CAUTION:
DO NOT probe the Powertrain Control Module (PCM) harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal-to-pin connection. Install Miller Special Tool (8815) to perform diagnosis.
Test Procedure
- Turn the ignition off. Disconnect the PCM harness connectors. See Fig 6 . Using a 12-volt test light connected to ground, probe the PCM C1 fused B+ circuit in the appropriate terminal of the Miller Special Tool (8815). See Fig 7 . Does the test light illuminate brightly? If yes, go to next step. If no, repair the PCM fused B+ circuit for an open. Check related fuses and repair as necessary.
- Turn the ignition on, with the engine off. Using 12-volt test light connected to ground, probe the fused ignition switch output circuits in the appropriate terminals of the Miller Special Tool (8815). See Fig 7 . Does the test light illuminate brightly? If yes, go to next step. If no, repair the fused ignition switch output circuit(s) for an open. Check related fuses and repair as necessary.
- Turn the ignition off. Using 12-volt test light connected to battery voltage, probe the PCM ground circuits in the appropriate terminals of the Miller Special Tool (8815). See Fig 7 . Does the test light illuminate brightly? If yes, the test is complete. If no, repair the PCM ground circuit(s) for an open.