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Home >> Cadillac >> 2017 >> ATS Base, 2D Coupe, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 199 (Power Door Lock System And Release Systems) >> Diagnostic Information and Procedures >> DTC B384A: Liftgate Close Switch Indicator Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2016 Cadillac CT6. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle Off and all vehicle systems Off.Disconnect the harness connector at the B70 Liftgate Close Switch. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 30 Ω between the low reference circuit terminal 1 and ground.
    • If 30 Ω or greater 
    1. Ignition/Vehicle Off.Disconnect the harness connector at the K39 Liftgate 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, repair the open/high resistance in the low reference connection.
    • If less than 30 Ω 
  3. Ignition On/Vehicle in Service Mode.
  4. Connect a test lamp between the control circuit terminal 2 and ground.
  5. Verify the test lamp turns ON and dims when commanding the LED Backlight Dimming Command with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition/Vehicle Off.Remove the test lamp, disconnect the harness connector at the K39 Liftgate 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 K39 Liftgate Control Module.
    • If the test lamp is always ON 
    1. Ignition/Vehicle Off.Remove the test lamp, disconnect the harness connector at the K39 Liftgate Control Module. Ignition On/Vehicle in Service Mode.
    2. Test for less than 1 V between the control 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 the test lamp turns ON and OFF 
  6. Test or replace the B70 Liftgate Close Switch.
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