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Tahoe / Yukon Service Manual

DTC C10A6

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. DTC Descriptors Axle Differential Lock Motor Temperature Sensor Signal Symptom Byte Information: Symptom Byte List Diagnostic Fault Information

Circuit Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
7978 Signal C10A6 11 C10A6 15 C10A6 15 —
7977 Low Reference — C10A6 15 — —

Circuit/System Description The axle differential lock motor temperature sensor is a thermistor. The K164 Differential Control Module supplies a signal circuit and a low reference circuit to the sensor. As the temperature rises/falls, the resistance in the thermistor changes to indicate the current temperature to the module. Conditions for Running the DTC Ignition ON System voltage is 9–16 V. Conditions for Setting the DTC The control module detects a fault in the temperature sensor signal circuit. Action Taken When the DTC Sets System is disabled — clutch open Service Rear Axle message sent to DIC Conditions for Clearing the DTC The control module clears the active DTC on the following key cycle once the conditions for setting the DTC are no longer present. A history DTC clears after 40 consecutive warm up cycles without a fault present. Reference Information Schematic Reference Differential Lock Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information. Circuit/System Testing

  1. Ignition OFF, disconnect the connector at the M135 Differential Lock Motor.
  2. Verify a test lamp illuminates between the low reference circuit terminal 8 and B+. ⇒ If the test lamp does not illuminate 2.1. Test circuit 7977 for an open/high resistance ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 2.2. Replace the K164 Differential Control Module. ⇓ If the test lamp illuminates
  3. Disconnect the X2 harness connector at the K164 Differential Control Module.
  4. Test for a short to ground on circuit 7978. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found.
  5. Ignition ON.
  6. Test circuit 7978 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found.
  7. Ignition OFF.
  8. Test circuit 7978 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found.
  9. Replace the M135 Differential Lock Motor.
  10. Operate the vehicle under the Conditions for Running the DTC.
  11. Verify the DTC does not reset. ⇒ If the DTC resets Replace the K164 Differential Control Module ⇓ If the DTC does not reset
  12. A fault is not currently present and may be an intermittent condition. Repair Instructions Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Limited Slip Differential Clutch Motor Replacement Control Module References