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Home >> GMC >> 2017 >> Acadia SL >> Repair and Diagnosis >> Accessories & Equipment >> Drivers Assistance Systems - ADAS >> Object Detection System And Pedestrian Protection System >> Diagnostic Information and Procedures >> DTC B0954, B0955, B0956, or B0957: Parking Assist Front Sensor >> Circuit/System Testing

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 10 Ω between the low reference circuit terminal 2 and ground.
    • If 10 Ω 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 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 K41 Front and Rear Parking Assist Control Module.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Test for 7.5-9.5 V between the 8 V reference circuit terminal 1 and ground.
    • If less than 7.5 V 
    1. Ignition OFF, disconnect the harness connector at the K41 Front and Rear Parking Assist Control Module.
    2. Test for infinite resistance between the 8 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 8 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 K41 Front and Rear Parking Assist Control Module.
    • If greater than 9.5 V 
    1. Ignition OFF, disconnect the harness connector at the K41 Front and Rear Parking Assist Control Module, ignition ON.
    2. Test for less than 1 V between the 8 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 K41 Front and Rear Parking Assist Control Module.
    • If between 7.5-9.5 V 
  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 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    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 2 Ω in the circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K41 Front and Rear Parking Assist Control Module.
    • If no DTC set 
  7. All OK.
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