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Tahoe / Yukon Service Manual

DTC C111A

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 Descriptor DTC C111A Axle Differential Lock Control High Diagnostic Fault Information

Circuit Number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
7968 Control C111A 11 C111A 13 C111A 12 C1135 77, C1135 98, C111A 19
7969 Control C111A 11 C111A 13 C111A 12 C1135 77, C1135 98, C111A 19

Circuit/System Description The K164 Differential Control Module is supplying voltage to the rear differential lock actuator motor and is grounded through the control module. Conditions for Running the DTC Ignition ON Conditions for Setting the DTC C111A 11 The differential control module detects a short to ground on the rear differential lock actuator motor circuit. C111A 12 The differential control module detects a short to battery on the rear differential lock actuator motor circuit. C111A 13 The differential control module detects an open on the rear differential lock actuator motor circuit. C111A 19 The differential control module detects high current on the rear differential lock actuator motor circuit. Action Taken When the DTC Sets One or more of the following actions may occur: The system is disabled for the duration of the key cycle. The SERVICE REAR AXLE message is displayed in the driver information center. Conditions for Clearing the DTC The condition for the DTC is no longer present. The DTC is not detected in 40 consecutive drive cycles. Reference Information Schematic Reference Differential Lock Schematics Connector End View Reference Master Electrical Component List Description and Operation Rear Drive Axle Description and Operation 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 X1 harness connector at the K164 Differential Control Module, ignition ON/Vehicle in Service Mode.
  2. Test for less than 1 V between the K164 Differential Control Module connector terminals listed below and ground. Terminal 1 Terminal 4 ⇒ If 1 V or greater Repair the short to voltage on the circuit. ⇓ If less than 1 V
  3. Ignition OFF.
  4. Test for infinite resistance between K164 Differential Control Module connector terminals listed below and ground. Terminal 1 Terminal 4 ⇒ If less than infinite resistance Repair the short to ground on the circuit. ⇓ If Infinite resistance
  5. Disconnect harness connector at the M135 Differential Lock Motor.
  6. Test for less than 2 Ω between M135 Differential Lock Motor connector terminal 3 and K164 Differential Control Module connector terminal 1 end to end. ⇒ If 2 Ω or greater Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
  7. Test for less than 2 Ω between M135 Differential Lock Motor connector terminal 2 and K164 Differential Control Module connector terminal 4 end to end. ⇒ If 2 Ω or greater Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
  8. Test or replace the M135 Differential Lock Motor.
  9. Operate the vehicle under the conditions for setting the DTC, the DTC should not set. ⇒ If the DTC sets Replace the K164 Differential Control Module. ⇓ If no DTC sets
  10. A fault is not currently present and may be an intermittent condition. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Limited Slip Differential Clutch Motor Replacement Control Module References for rear differential clutch control module replacement, programming, and setup.