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Home >> Cadillac >> 2017 >> XT5 Base >> Repair and Diagnosis >> Accessories & Equipment >> Anti-Theft Systems >> Power Door Lock System And Release Systems >> Diagnostic Information and Procedures >> DTC B396A: Liftgate Motor Power Open/Close Malfunction >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the X2 harness connector at the K39 Liftgate Control Module, Ignition ON
  2. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Disconnect the harness connector at the M17 Liftgate Motor Assembly.
    4. Test for infinite resistance between each control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the M17 Liftgate Motor Assembly.
    • If the test lamp illuminates 
  3. Ignition OFF, connect the X2 harness connector at the K39 Liftgate Control Module and disconnect the X1 harness connector at the M17 Liftgate Motor Assembly.
  4. Connect a test lamp between the control circuit terminal 1 and control circuit terminal 2, ignition ON.
  5. Liftgate closed and latched, verify the test lamp turns ON and OFF when pressing the S46B Liftgate Unlatch Switch.
    • If the test lamp remains OFF 
    6. NOTE:

    The liftgate must be opened and allowed to cinch closed each time this test is performed, repeating this test without opening and closing the liftgate will result in a misdiagnosis and replacement of a functional K39 Liftgate Control Module

  6. Open and completely close the liftgate, verify the test lamp turns ON and OFF when pressing the S46B Liftgate Unlatch Switch.
    • If the test lamp remains OFF 
    1. Ignition OFF, remove the test lamp, disconnect the X3 harness connector at the K39 Liftgate Control Module.
    2. Test for infinite resistance between each control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the control circuits end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K39 Liftgate Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, remove the test lamp, disconnect the X3 harness connector at the K39 Liftgate Control Module, ignition ON.
    2. Test for less than 1 V between each control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K39 Liftgate Control Module
    • If the test lamp turns ON and Off 
  7. Replace the M17 Liftgate Motor Assembly.
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