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Circuit/System Testing

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DTC B3948

  1. Ignition OFF, disconnect the X5 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 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 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 X5 harness connector at the K9 Body Control Module.
  4. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E4 Turn Signal Lamp - Left bulb. It may take up to 2 min for all vehicle systems to power down.
  5. Test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground.
    • E4LF Turn Signal Lamp - Left Front terminal 2
    • E4Y Turn Signal Repeater Lamp - Left terminal 1 (with T90)
    • A9A Outside Rearview Mirror - Driver terminal 5 (LHD without T90)
    • A9B Outside Rearview Mirror - Passenger terminal 5 (RHD without T90)
    • E4N Park/Turn Signal Lamp - Left terminal C
    • 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.
    • E4LF Turn Signal Lamp - Left Front terminal 1
    • E4Y Turn Signal Repeater Lamp - Left terminal 2 (with T90)
    • A9A Outside Rearview Mirror - Driver terminal 3 (LHD without T90)
    • A9B Outside Rearview Mirror - Passenger terminal 3 (RHD without T90)
    • E4N Park/Turn Signal Lamp - Left terminal A
  7. Verify the test lamp turns ON and OFF when commanding the Left Front Turn Signal Lamp ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X5 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 X5 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 E4 Turn Signal Lamp - Left bulb.

DTC B3949

  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 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 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 E4 Turn Signal Lamp - Right bulb. It may take up to 2 min for all vehicle systems to power down.
  5. Test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground.
    • E4RF Turn Signal Lamp - Right Front terminal 2
    • E4Z Turn Signal Repeater Lamp - Right terminal 1 (with T90)
    • A9A Outside Rearview Mirror - Driver terminal 5 (RHD without T90)
    • A9B Outside Rearview Mirror - Passenger terminal 5 (LHD without T90)
    • E4P Park/Turn Signal Lamp - Right terminal C
    • 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.
    • E4RF Turn Signal Lamp - Right Front terminal 1
    • E4Z Turn Signal Repeater Lamp - Right terminal 2 (with T90)
    • A9A Outside Rearview Mirror - Driver terminal 3 (RHD without T90)
    • A9B Outside Rearview Mirror - Passenger terminal 3 (LHD without T90)
    • E4P Park/Turn Signal Lamp - Right terminal A
  7. Verify the test lamp turns ON and OFF when commanding the Right Front Turn Signal Lamp 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 E4 Turn Signal Lamp - Right bulb.
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