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Circuit/System Testing

  1. With a scan tool, verify DTC U0100-U0299 or U2105-U2199 is not set as current.
  2. Ignition OFF, test for less then 5 Ω between the applicable module ground circuit and ground.
    • If greater then the specified range, test the circuit for an open/high resistance.
  3. Ignition OFF, disconnect the applicable module harness connector.
  4. Ignition ON, verify a test lamp illuminates between the following circuits of the applicable module and ground.
    • The battery positive voltage input circuits.
    • The battery positive voltage output circuits.
    • The ignition voltage input circuits.
    • The ignition voltage output circuits.
    • The switched battery positive voltage supply circuits.
    • If the test lamp does not illuminate, test the circuit for an open/high resistance. If the circuit fuse is open, test the circuit for a short to ground. If the circuit tests normal, replace the applicable control module.
  5. Ignition OFF, test for less then 5 Ω between the non-communicating modules GMLAN serial data circuits and the module reporting DTC U0002.
    • If greater then the specified range, test the circuit for and open/high resistance.
  6. If all circuits test normal, replace the applicable control module.
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