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Circuit/System Testing

WARNING: This page is about a different car, the 2011 Chevrolet Caprice. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the SIM harness connector.
  2. Test for less than 1 ohm between the module ground circuits and ground.
    • If greater than 1 ohm, repair the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between all battery positive voltage circuits and ground.
    • If the test lamp does not illuminate, repair the circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the SIM.
  4. Verify that a test lamp illuminates between all ignition voltage circuits and ground.
    • If the test lamp does not illuminate, repair the circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the SIM for a short to ground. If the circuits test normal, replace the SIM.
  5. Ignition ON, verify that a test lamp illuminates between the serial data communication enable circuit OR the accessory wakeup serial data circuit and ground.
    • If the test lamp does not illuminate, repair the circuit for an open/high resistance. If the circuits test normal, replace the BCM.
  6. Test for less than 1 ohm in the low speed GMLAN serial data circuit between the SIM and the module that displays the DTC.
    • If greater than 1 ohm, test the low speed GMLAN serial data circuit for open/high resistance.
  7. If all circuits test normal, replace the SIM.
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