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Home >> Buick >> 2015 >> Regal GS, FWD, Automatic Trans >> Repair and Diagnosis >> Accessories & Equipment >> Drivers Assistance Systems - ADAS >> Object Detection And Pedestrian Protection System >> Diagnostic Information and Procedures >> DTC B0954, B0955, B0956, or B0957: Parking Assist Front Sensor >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, scan tool disconnected, disconnect the harness at the appropriate B78 Front Object Sensor. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10Ω between the low reference circuit terminal 2 and ground.
    • If 10Ω or greater 
    1. Ignition OFF, disconnect the harness connector X3 at the K41 Front and Rear Parking Assist Control Module.
    2. Test for less than 2Ω in the low reference circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω replace the K41 Front and Rear Parking Assist Control Module.
    • If less than 10Ω 
  3. Ignition ON.
  4. Test for 7.5-9.5V between the 8V reference circuit terminal 1 and ground.
    • If less than 7.5V 
    1. Ignition OFF, disconnect the harness connector at the K41 Front and Rear Parking Assist Control Module.
    2. Test for infinite resistance between the 8V 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 2Ω in the 8V reference circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K41 Front and Rear Parking Assist Control Module.
    • If greater than 9.5V 
    1. Ignition OFF, disconnect the harness connector at the K41 Front and Rear Parking Assist Control Module, ignition ON.
    2. Test for less than 1V between the 8V reference circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K41 Front and Rear Parking Assist Control Module.
    • If between 7.5-9.5V 
  5. Ignition OFF, remove appropriate B78 Front Object Sensor and switch locations with another properly operating sensor. Connect harness connector at both sensors. Ignition ON.
  6. Verify the DTC is set for the new location in which the malfunctioning sensor is installed.
    • If DTC set for the new location 

      Replace the malfunctioning B78 Front Object Sensor.

    • If DTC set for the original location 
    1. Ignition OFF, disconnect the harness connector at the K41 Front and Rear Parking Assist Control Module, ignition ON.
    2. Test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V
    3. Ignition OFF.
    4. 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
    5. Test for less than 2Ω in the circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K41 Front and Rear Parking Assist Control Module.
    • If no DTC set 
  7. All OK.
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