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Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition on, with engine off. Using scan tool, perform IGNITION COIL CYL NO. 1-6 test for each individual cylinder. Listen closely for spark at appropriate ignition coil. If spark is not audible at a specific cylinder, go to next step. If spark is not audible on a specific EI module, go to step  4 . If spark is not audible on all cylinder, check for open ENG/IGN (15A) fuse or for faulty engine ground circuit. See Figure . Repair as necessary. If fuse continuously opens, check for shorted power circuit from underhood fuse block to EI module. See Figure .
  2. Disconnect harness connector to affected EI module. Connect a test light between battery voltage and respective ignition coil ECM driver circuit. See Figure . Using scan tool, command appropriate ignition coil on. If test light does not illuminate, go to next step. If test light pulses, check ECM driver circuit terminal for tightness at EI module. Repair as necessary. If terminal is okay, replace EI module. If test light is always on, check ECM driver circuit for short to ground. Repair as necessary. If circuit is okay, replace ECM.
  3. Connect test light between ground and specific ECM driver circuit at harness connector. If test light illuminates, repair short to voltage in circuit. See Figure . If test light does not illuminate, check specific circuit for open and terminal tightness at ECM. Repair as necessary. If circuit or terminal is okay, replace ECM.
  4. Turn ignition off. Disconnect appropriate EI module harness connector. Turn ignition on, with engine off. Connect a test light between ground and EI harness connector terminal No. 2 (Pink wire). See Figure . If test light illuminates, go to next step. If test light does not illuminate, repair open in circuit.
  5. Connect test light between battery voltage and EI harness connector terminal No. 1 (Black/White wire). If test light does not illuminate, repair open in circuit. If test light illuminates, check EI module harness connector for terminal tightness. Repair as necessary. If terminals are okay, replace EI module.
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