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Home >> Cadillac >> 2013 >> SRX Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 189 (Power Door Lock System And Release Systems) >> Diagnostic Information and Procedures >> DTC B153F: Liftgate Object Sensor Malfunction >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2015 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the B71L Liftgate Object Sensor - Left. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal B and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    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 10 Ω 
  3. Disconnect the harness connector at the B71R Liftgate Object Sensor - Right.
  4. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connector at the K39 Liftgate 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 K39 Liftgate Control Module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the harness connector at the K39 Liftgate 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 K39 Liftgate Control Module.
    • If between 4.8-5.2 V 
  5. Test or replace the B71 Liftgate Object Sensors.
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