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Home >> Cadillac >> 2007 >> Escalade ESV >> Repair and Diagnosis >> External Pages >> Different car >> Section 1441 (Engine Controls And Fuel - Hybrid (Hp2) 6.0L (LFA) - Troubleshooting & Diagnosis) >> Electronic Ignition System Diagnosis >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description .
  2. Ignition ON, verify the scan tool hood position parameter displays Open.
    3. IMPORTANT: This engine application uses 2 fuses, one for each bank, to supply ignition 1 voltage to the ignition module/coil assemblies and also to the fuel injectors. A good indication that a fuse is open is that all 4 misfire counters are incrementing on one side of the engine
  3. Inspect both fuses that supply ignition voltage to the ignition module/coils.
    • If a fuse is open, test all 8 ignition voltage circuits to the ignition module/coils or the fuel injectors on that engine bank, for a short to ground.
  4. Disconnect the 4 ignition module/coil, and the 4 fuel injector electrical connectors, for the engine bank that has the open fuse.
  5. Replace the open fuse with a new fuse.
  6. Ignition ON, engine OFF.
  7. Reconnect each ignition module/coil, and fuel injector electrical connectors, one at a time.
    • If the fuse opens when connecting an ignition module/coil or fuel injector electrical connector, then replace the component that caused the fuse to open.
  8. Ignition OFF, disconnect the appropriate ignition module/coil electrical connector.
  9. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit and ground.
    • If the test lamp does not illuminate test the ignition voltage circuit for an open/high resistance.
  10. Verify that a test lamp illuminates between the ignition module/coil ground circuit and B+.
    • If the test lamp does not illuminate, test the ignition module/coil ground circuit for an open/high resistance.
  11. Inspect and measure the resistance of the spark plug wire. Refer to Spark Plug Wire Inspection and Ignition System Specifications .
    • If the resistance value is not within the specified range, or does not pass the inspection, replace the spark plug wire.
  12. Exchange the misfiring cylinder, ignition module/coil assembly with the ignition module/coil assembly from a non-misfiring cylinder.
  13. Start and idle the engine. Observe the misfire counters on the scan tool.
    • If the misfire transfers with the suspect ignition module/coil, then replace the ignition module/coil assembly.
    • If the misfire does not transfer with the suspect ignition module/coil, then measure the resistance of the IC circuit. The IC circuit should measure less than 5 ohms. If the circuit tests normal, replace the ECM.
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