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Tahoe / Yukon Service Manual

DTC C2A21

Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC C2A21 Park Brake Actuator Position Unknown Symptom Byte Information: Symptom Byte List Circuit/System Description For an overview of the component/system, refer to: Electronic Parking Brake Description

Component Description
Park Brake Actuator The park brake function uses the same brake pads as the operational brake. An electric motor is used to apply and release the brake pads.
K160 Brake System Control Module The control module K160 can increase and decrease the brake pressure on all 4 wheels individually in order to fulfill these functions: Antilock Braking Traction Control Vehicle Stability Control The control module K160 can also influence the following control modules to limit the amount of produced torque: K20 Engine Control Module K71 Transmission Control Module

Conditions for Running the DTC Ignition = On or Vehicle = Service Mode System Voltage = 9 to 16 V Conditions for Setting the DTC Park Brake Actuator Status = Unknown Actions Taken When the DTC Sets A message and/or warning indicator may be displayed to the driver. Conditions for Clearing the DTC The conditions for setting the DTC no longer exist. A history DTC will clear after 40 consecutive malfunction-free ignition cycles. Diagnostic Aids If a message displays on the Driver Information Center (DIC) that indicates the transmission is unable to shift soon, the service electric parking brake light is on, and the Electric Parking Brake (EPB) light flashes at the same time, the system must be reset. The 12 V battery must be fully charged. Start the vehicle, apply the EPB and then release it. The message and the light should turn off. Reference Information Schematic Reference Park Brake System 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 Circuit/System Verification

  1. Ignition » On / Vehicle » In Service Mode
  2. Verify DTC C2A21 is not set. ⇒ If the DTC is set 2.1. Perform the following learn procedure: Park Brake Calibration. 2.2. Apply the electronic parking brake. 2.3. Release the parking brake. 2.4. Verify DTC C2A21 is not set. ⇒ If the DTC is set Perform all necessary programming and setup procedures for the control module: K160  Brake System Control Module ⇓ If the DTC is not set All OK. ⇓ If the DTC is not set
  3. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification For control module replacement, programming, and setup refer to: Control Module References