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Circuit/System Testing

WARNING: This page is about a different car, the 2015 Buick Verano. However, it is still accessible from the selected car via links, so may be relevant.

DTC B2585

  1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, disconnect the X1 harness connector at the X51A Fuse Block - Instrument Panel.
    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, disconnect the X1 harness connector at the X51A Fuse Block - Instrument Panel.
    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, replace the K9 Body Control Module.
    • If the test lamp illuminates 
  3. Ignition OFF, connect the X2 harness connector at the K9 Body Control Module.
  4. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate left park lamp.
  5. Test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground.
    • E5AA Tail/Stop Lamp - Left - terminal 3
    • E2LR Side Marker Lamp - Left Rear - terminal 2
    • E5AK Tail Lamp - Left Outer - terminal 2
    • E5G Tail Lamp - Left Inner - terminal 2
    • E4N Park/Turn Signal Lamp - Left - terminal 3
    • If 5 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 5 Ω 
  6. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.
    • E5AA Tail/Stop Lamp - Left - terminal 1
    • E2LR Side Marker Lamp - Left Rear - terminal 1
    • E5AK Tail Lamp - Left Outer - terminal 1
    • E5G Tail Lamp - Left Inner - terminal 1
    • E4N Park/Turn Signal Lamp - Left - terminal 1
  7. Verify the test lamp turns ON and OFF when commanding the Left Park Lamps ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the 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 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, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the control circuit terminal 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.
    • If the test lamp turns ON and OFF 
  8. Test or replace the appropriate left park lamp.

DTC B3867

  1. Ignition OFF, disconnect the X2 harness connector at the K9 Body 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, disconnect the X1 harness connector at the X51A Fuse Block - Instrument Panel.
    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, disconnect the X1 harness connector at the X51A Fuse Block - Instrument Panel.
    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, replace the K9 Body Control Module.
    • If the test lamp illuminates 
  3. Ignition OFF, connect the X2 harness connector at the K9 Body Control Module.
  4. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate right park lamp.
  5. Test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground.
    • E5AB Tail/Stop Lamp - Right - terminal 3
    • E2RR Side Marker Lamp - Right Rear - terminal 2
    • E5AL Tail Lamp - Right Outer - terminal 2
    • E5H Tail Lamp - Right Inner - terminal 2
    • E4P Park/Turn Signal Lamp - Right - terminal 3
    • If 5 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 5 Ω 
  6. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.
    • E5AB Tail/Stop Lamp - Right - terminal 1
    • E2RR Side Marker Lamp - Right Rear - terminal 1
    • E5AL Tail Lamp - Right Outer - terminal 1
    • E5H Tail Lamp - Right Inner - terminal 1
    • E4P Park/Turn Signal Lamp - Right - terminal 1
  7. Verify the test lamp turns ON and OFF when commanding the Right Park Lamps ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the 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 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, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the control circuit terminal 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.
    • If the test lamp turns ON and OFF 
  8. Test or replace the appropriate right park lamp.
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