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Home >> Jeep >> 2003 >> Wrangler X, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Computerized Engine Controls >> Powertrain Control Module >> Checking Powertrain Control Module (PCM) Power & Ground Circuits
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Checking Powertrain Control Module (PCM) Power & Ground Circuits

  1. Turn ignition off. Disconnect the PCM Black C1 harness connector. Using a 12-volt test light connected to ground, probe the PCM Fused B+ circuit in the PCM harness connector. Does the test light illuminate brightly? If yes, go to next step. If no, repair the Fused B+ circuit for an open. Perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS in SELF-DIAGNOSTICS - WRANGLER article.
  2. Turn ignition on. Using a 12-volt test light connected to ground, probe the Fused Ignition Switch Output circuit in the PCM C1 harness connector. Does the test light illuminate brightly? If yes, go to next step. If no, repair the Ignition Switch Output circuit for an open. Perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS in SELF-DIAGNOSTICS - WRANGLER article.
  3. Turn ignition off. Using a 12-volt test light connected to battery voltage, probe the PCM ground circuits in the PCM C1 harness connector. Does the test light illuminate brightly? If yes, test is complete. If no, repair the PCM ground circuit for an open. Perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS in SELF-DIAGNOSTICS - WRANGLER article.
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