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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 350 (Rear Drive Axle) >> Diagnostic Information and Procedures >> DTC C0393: Rear Differential Clutch Solenoid Valve Control Circuit (G99) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 GMC Acadia. 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, Ignition ON/Vehicle in Service Mode.
  2. Test for 6.4-6.6 V between the control circuit terminal 3 and ground.
    • If less than 6.4 V 
    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 terminal 3 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 terminal 3 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 greater than 6.6 V 
    1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, Ignition ON/Vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit terminal 3 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 between 6.4-6.6 V 
  3. Test for 4.9-5.3 V between the control circuit terminals listed below and ground.
    • Control Circuit Terminal 2
    • Control Circuit Terminal 1
    • If less than 4.9 V 
    1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
    2. Test for infinite resistance between the appropriate control circuit terminal 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 appropriate control circuit terminal 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 greater than 5.3 V 
    1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, Ignition ON/Vehicle in Service Mode.
    2. Test for less than 1 V between the appropriate control circuit terminal 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 between 4.9-5.3 V 
  4. Test or replace the Q49 Rear Differential Clutch Solenoid Valve.
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