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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 217 (Rear Drive Axle) >> Diagnostic Information and Procedures >> DTC C0393: Rear Differential Clutch Solenoid Valve Control Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the Q49 Rear Differential Clutch Solenoid Valve.
  2. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Rear Differential Clutch Solenoid Valve between 0% and 10%.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, ignition ON.
    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 K47 Rear Differential Clutch Control Module.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch 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 K47 Rear Differential Clutch Control Module.
    • If the test lamp turns ON and OFF 
  4. Connect a test lamp between the control circuit terminal 1 and control circuit terminal 2.
  5. Verify the test lamp get progressively brighter when commanding the Rear Differential Clutch Solenoid Valve between 0% and 100%.
    • If the test lamp does not get progressively brighter 
    1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, ignition ON.
    2. Test for less than 1 V between the control circuit terminal 2 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V.
    3. Test for infinite resistance between the control circuit terminal 2 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    4. Test for less than 2 Ω in the control circuit terminal 2 end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K47 Rear Differential Clutch Control Module.
    • If the test lamp does get progressively brighter 
  6. Replace the Q49 Rear Differential Clutch Solenoid Valve.
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