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Circuit/System Testing

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the affected ignition coil/modules.
  2. Ignition OFF for 90 seconds, test for less than 5 ohms between the ground circuit terminal A and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Test for less than 5 ohms between the low reference circuit terminal B and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
    4. IMPORTANT: If the ignition voltage fuse is open, it will be necessary to test the spliced ignition circuits and the components for a short to ground.
  4. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal D and ground.
    • If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance.
  5. Exchange the affected ignition coil/module with the ignition coil/module of a good cylinder.
  6. Start the engine, and observe the scan tool Misfire Current Cylinder parameters.
    • If the misfire transfers with the suspect ignition coil/module, replace as needed.
  7. If the circuits test normal, test or replace the spark plug/s.
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