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Home >> Cadillac >> 2018 >> CT6 Plug-In >> Repair and Diagnosis (Single Page) >> Electrical >> Body Electrical >> Wiring Systems And Power Management - Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC B1445 (Body Control Module) >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF/Vehicle OFF and all vehicle systems OFF, disconnect the P2 Transmission Shift Lever Position Indicator.
  2. Connect a test lamp between the ignition circuit terminal 3 and ground, Ignition ON/Vehicle in Service Mode.
  3. Verify the test lamp turns ON and OFF when commanding the Accessory/Retained Accessory Power Relay On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, remove test lamp, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance.
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF/Vehicle OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON/Vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 Body Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Test or replace the P2 Transmission Shift Lever Position Indicator.
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