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Home >> Chevrolet >> 2021 >> Traverse LS, FWD >> Repair and Diagnosis >> Drivelines & Axles >> Differentials & Drive Axles >> Rear Drive Axle >> Diagnostic Information and Procedures >> DTC C056D >> Circuit/System Testing

Circuit/System Testing

Test 1

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M115 Power Transfer Unit Shift Actuator. 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 3 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the X1 harness connector at the K47 Rear Differential Clutch 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 K47 Rear Differential Clutch Control Module.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/Vehicle In Service Mode.
  4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 2 and ground.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the X1 harness connector at the K47 Rear Differential Clutch 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.
      • Go to next step: 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 K47 Rear Differential Clutch Control Module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the X1 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 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 K47 Rear Differential Clutch Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Ignition ON/Vehicle In Service Mode.
  6. Test for 4.6 - 5.6 V between the signal circuit terminal 1 and ground.
    • If less than 4.6 V 
    1. Ignition OFF, disconnect the X1 harness connector at the K47 Rear Differential Clutch Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the signal 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 greater than 5.6 V 
    1. Ignition OFF, disconnect the X1 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 signal 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.
    • Go to next step: If between 4.6 - 5.6 V 
  7. Test or replace the M115 Power Transfer Unit Shift Actuator.
  8. Operate the vehicle under the conditions for setting the DTC, the DTC should not set.
    • If the DTC sets 

      Replace the K47 Rear Differential Clutch Control Module.

    • Go to next step: If the DTC does not set 
  9. All OK.

Test 2

  1. Ignition OFF, disconnect the X1 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 K47 Rear Differential Clutch Control Module harness connector terminals listed below and ground.
    • Terminal 1
    • Terminal 12
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  3. Ignition OFF.
  4. Test for infinite resistance between K47 Rear Differential Clutch Control Module harness connector terminals listed below and ground.
    • Terminal 1
    • Terminal 12
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If Infinite resistance 
  5. Disconnect harness connector at the M115 Power Transfer Unit Shift Actuator.
  6. Test for less than 2 Ω between M115 Power Transfer Unit Shift Actuator harness connector terminal 4 and K47 Rear Differential Clutch Control Module harness connector terminal 1 end to end.
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
  7. Test for less than 2 Ω between M115 Power Transfer Unit Shift Actuator harness connector terminal 5 and K47 Rear Differential Clutch Control Module harness connector terminal 12 end to end.
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
    8. NOTE:

    DTC C1295 may set due to a mechanical issue within the power transfer unit in which the unit is not physically engaging, despite being commanded to do so.

  8. Visually inspect the power transfer unit for any signs of mechanical damage or other conditions which may prevent the unit from physically engaging. This may require disassembly of the power transfer unit. Refer to Power Transfer Unit Case Disassemble .
    • If damage is found 

      Repair as necessary.

    • Go to next step: If no damage is found 
  9. Test or replace the M115 Power Transfer Unit Shift Actuator.
  10. Operate the vehicle under the conditions for setting the DTC, the DTC should not set.
    • If the DTC sets 

      Replace the K47 Rear Differential Clutch Control Module.

    • Go to next step: If no DTC sets 
  11. All OK

Test 3

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M115 Power Transfer Unit Shift Actuator. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 4.2 KΩ between the low reference circuit terminal 4 and ground.
    • If 4.2 KΩ or greater 
    1. Ignition OFF, disconnect the X1 harness connector at the K47 Rear Differential Clutch 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 K47 Rear Differential Clutch Control Module.
    • Go to next step: If less than 4.2 KΩ 
  3. Ignition ON/Vehicle In Service Mode.
  4. Test for 5.8 - 6.2 V between the control circuit terminal 5 and ground.
    • If less than 5.8 V 
    1. Ignition OFF, disconnect the X1 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.
      • Go to next step: 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 greater than 6.2 V 
    1. Ignition OFF, disconnect the X1 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 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.
    • Go to next step: If between 5.8 - 6.2 V 
  5. Ignition OFF, disconnect the X1 harness connector at the K47 Rear Differential Clutch Control Module, ignition ON/Vehicle In Service Mode.
  6. Test for less than 1 V between the M115 harness connector terminals listed below and ground.
    • Terminal 4
    • Terminal 5
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  7. Ignition OFF.
  8. Test for infinite resistance between M115 harness connector terminals listed below and ground.
    • Terminal 4
    • Terminal 5
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If Infinite resistance 
  9. Test for less than 2 Ω between M115 Power Transfer Unit Shift Actuator harness connector terminal 4 and K47 Rear Differential Clutch Control Module harness connector terminal 1 end to end.
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 2 Ω 
  10. Test for less than 2 Ω between M115 Power Transfer Unit Shift Actuator harness connector terminal 5 and K47 Rear Differential Clutch Control Module harness connector terminal 12 end to end.
  11. Test or replace the M115 Power Transfer Unit Shift Actuator.
  12. Operate the vehicle under the conditions for setting the DTC, the DTC should not set.
    • If the DTC sets 

      Replace the K47 Rear Differential Clutch Control Module.

    • Go to next step: If the DTC does not set 
  13. All OK.
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