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Circuit/System Testing

NOTE:

Use the schematic to determine which control modules are on the BCM communications enable circuit 23, X4.

  1. Ignition OFF, disconnect the harness connector at the most easily accessible control module on the K9 BCM communication enable circuit.
  2. Ignition ON, retest for current DTCs. DTC U2099 should remain current.
    • If the DTC becomes history, replace the control module that was just disconnected.
  3. With the prior control modules disconnected, repeat steps 1 and 2 for each control module on the circuit except the K9 BCM.
  4. Ignition OFF, disconnect the X4 harness connector at the K9 BCM.
  5. Test for infinite resistance between the serial data communication enable circuit terminal 23 X4 and ground.
    • If less than infinite resistance, repair the communication enable circuit for a short to ground.
  6. If all circuits tests normal, replace the K9 BCM.
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