Checking Powertrain Control Module Power & Ground Circuits (3.9L & 5.9L)

Possible Causes

• (A14) PCM Fused B+ Circuit
• (F18) PCM Fused Ignition Switch Output Circuit
• PCM Ground Circuits

Test Procedure

1. Turn the ignition off. Disconnect the Powertrain Control Module (PCM) harness connectors. See Figure . Using a 12-volt test light connected to ground, probe the (A14) fused B+ circuit in the PCM C1 harness connector. See Figure . Does the test light illuminate brightly? If yes, go to next step. If no, repair the (A14) fused B+ circuit for an open.
2. Turn the ignition on, with the engine off. Using 12-volt test light connected to ground, probe the (F18) PCM fused ignition switch output circuit in the PCM C1 harness connector. See Figure . Does the test light illuminate brightly? If yes, go to next step. If no, repair the (F18) PCM fused ignition switch output circuit for an open.
3. Turn the ignition off. Using 12-volt test light connected to battery voltage, probe the (Z12) PCM ground circuits in the PCM C1 harness connector. See Figure . Does the test light illuminate brightly? If yes, the test is complete. If no, repair the (Z12) PCM ground circuit(s) for an open.