LEMON Manuals: Even more car manuals for everyone
Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 64 (Rear Drive Axle - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC C1058, C1060, C10A7, or C1172 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF and all vehicle systems OFF, disconnect the connector at the M135 Differential Lock Motor. It may take up to 2 min for all vehicle systems to power down.
  2. Verify a test lamp illuminates between the low reference circuit terminal 9 and B+.
    • If the test lamp does not illuminate 
    1. Test circuit 7974 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit or ground connection.
      • Go to next step: If an open/high resistance is not found.
    2. Replace the K164 Differential Control Module.
    • Go to next step: If the test lamp illuminates 
  3. Ignition ON/Vehicle In Service Mode.
  4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 4 and ground.
    • If less than 4.8 V 
    1. Ignition OFF.
    2. Test circuit 7973 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found.
    3. Test circuit 7973 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found.
    4. Replace the K164 Differential Control Module.
    • If greater than 5.2 V 
    1. Test circuit 7973 for a short to voltage.
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found.
    2. Replace the K164 Differential Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Connect the connector at the M135 Differential Lock Motor.
  6. Ignition ON. Verify DTC C1058 or C1060 do not set.
    • If any of the DTCs set 
    1. Test the appropriate circuit for a short to ground:
      • DTC C1058 = Circuit 7975
      • DTC C1060 = Circuit 7976
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found.
    2. Test the appropriate circuit for a short to voltage:
      • DTC C1058 = Circuit 7975
      • DTC C1060 = Circuit 7976
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found.
    3. Test the appropriate circuit for an open/high resistance:
      • DTC C1058 = Circuit 7975
      • DTC C1060 = Circuit 7976
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found.
    4. Replace the K164 Differential Control Module.
    5. Operate the vehicle under Conditions for Running the DTC.
    6. Verify the DTCs do not set.
      • If the DTCs set

        Replace the M135 Differential Lock Motor.

      • Go to next step: If the DTCs do not set
    7. All OK.
    • Go to next step: If none of the DTCs set 
  7. A fault is not currently present and may be an intermittent condition.
scientia non olet · About LEMON Manuals