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Tahoe / Yukon Service Manual

DTC C1135

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 C1135 Differential Lock Motor Diagnostic Fault Information

Circuit Number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
7968 Control C1135 92 C1135 13 C1135 92 C1135 67, C1135 71, C1135 77, C1135 98
7969 Control C1135 92 C1135 13 C1135 92 C1135 67, C1135 71, C1135 77, C1135 98

Circuit/System Description 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. System voltage is between 9–16 V. Operation requested Conditions for Setting the DTC C1135 13 or C1135 92 The differential control module detects a fault on the rear differential lock actuator motor circuit. C1135 67 Differential lock motor signal incorrect after event. C1135 71 Differential lock motor actuator stuck. C1135 77 Differential lock motor commanded position not reachable. C1135 98 Differential lock motor component or system over temperature. Action Taken When the DTC Sets One or more of the following actions may occur: System is disabled — clutch open SERVICE REAR AXLE message is displayed in the Driver Information Center. Conditions for Clearing the DTC A current DTC clears on the following key cycle after the malfunction is no longer present. A history DTC clears when the device ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction. Diagnostic Aids DTC C1135 77 can set due to DTC C10A7 13. If DTC C10A7 13 is set as current or history, circuit 7973 should be checked first. 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 C1135 13 or C1135 92

  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 harness 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 harness 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 harness connector terminal 3 and K164 Differential Control Module harness 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 harness connector terminal 2 and K164 Differential Control Module harness 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. All OK C1135 67, C1135 71, C1135 77, or C1135 98
  11. Verify there are no other DTCs set. ⇒ If any other DTCs are set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If no other DTCs are set
  12. Check for updated software in K164 Differential Control Module. ⇒ If software is not current 2.1. Perform programming procedure for the K164 Differential Control Module. 2.2. Perform the Rear Differential Clutch Learn in the scan tool. ⇒ If Rear Differential Clutch Learn fails Replace the M135 Differential Lock Motor. ⇓ If Rear Differential Clutch Learn passes 2.3. Perform Rear Differential Functional Test using the scan tool. ⇒ If Rear Differential Functional Test fails and other DTCs set Diagnose DTCs. Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇒ If Rear Differential Functional Test fails and no other DTCs set Replace the M135 Differential Lock Motor. ⇓ If Rear Differential Function Test passes 2.4. All OK. ⇓ If software is up to date
  13. Perform the Rear Differential Clutch Learn in the scan tool. ⇒ If Rear Differential Clutch Learn fails Replace the M135 Differential Lock Motor. ⇓ If Rear Differential Clutch Learn passes
  14. Perform Rear Differential Functional Test using the scan tool. ⇒ If Rear Differential Functional Test fails and other DTCs set Diagnose DTCs. Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇒ If Rear Differential Functional Test fails and no other DTCs set Replace the M135 Differential Lock Motor. ⇓ If Rear Differential Function Test passes
  15. Operate the vehicle under Conditions for Setting DTCs.
  16. Verify DTC does not reset. ⇒ If DTC resets 6.1. Replace the M135 Differential Lock Motor. 6.2. Perform the Rear Differential Clutch Learn in the scan tool. ⇒ If Rear Differential Clutch Learn fails Replace the Differential. ⇓ If Rear Differential Clutch Learn passes 6.3. Perform Rear Differential Functional Test using the scan tool. ⇒ If Rear Differential Functional Test fails and other DTCs set Diagnose DTCs. Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇒ If Rear Differential Functional Test fails and no other DTCs set Replace the Differential. ⇓ If Rear Differential Function Test passes
  17. A fault is not currently present and may be an intermittent condition. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Differential Replacement Limited Slip Differential Clutch Motor Replacement for M135 Differential Lock Motor Replacement Control Module References for rear differential clutch control module replacement, programming, and setup.