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Home >> Cadillac >> 2015 >> SRX Base, 4D Utility >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Headlights >> Lighting System - Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC B3415: Automatic Headlamp Leveling Control Module Axle Sensor >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate B51 headlamp leveling sensor, ignition ON.
  2. Verify a test lamp illuminates between the low reference circuit terminal 2 and B+.
    • If the test lamp does not illuminate 
    1. Ignition OFF, disconnect the X2 harness connector at the K28 headlamp leveling control module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K28 headlamp leveling control module.
    • If the test lamp illuminates 
  3. Engine RUNNING.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the X2 harness connector at the K28 headlamp leveling control module.
    2. Test for infinite resistance between the 5 V reference 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 5 V reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K28 headlamp leveling control module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the X2 harness connector at the K28 headlamp leveling control module, ignition ON.
    2. Test for less than 1 V between the 5 V reference circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K28 headlamp leveling control module.
    • If between 4.8-5.2 V 
  5. Verify the appropriate scan tool Leveling Position Sensor parameter is less than 1 V.
    • If 1 V or greater 
    1. Ignition OFF, disconnect the X2 harness connector at the K28 headlamp leveling control module, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 3 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K28 headlamp leveling control module.
    • If less than 1 V 
  6. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and the signal circuit terminal 3, engine RUNNING.
  7. Verify the appropriate scan tool Leveling Position Sensor parameter is greater than 4.8 V.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the X2 harness connector at the K28 headlamp leveling control module.
    2. Test for infinite resistance between the signal 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 signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K28 headlamp leveling control module.
    • If 4.8 V or greater 
  8. Test or replace the appropriate B51 headlamp leveling sensor.
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