Skip to content
Tahoe / Yukon Service Manual

DTC C0609

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 provide an overview of each diagnostic category. DTC Descriptors DTC C0609 Park Brake Switch Circuit For symptom byte information, refer to: Symptom Byte List Circuit/System Description The parking brake function is integrated into the Brake System Control Module. The Brake System Control Module contains the logic for applying and releasing the parking brake when commanded by the Park Brake Switch. The Brake System Control Module will perform diagnostics on the Park Brake Switch and its wiring harness to verify it is functioning properly. The Park Brake Switch diagnostic checks for failure conditions in the Park Brake Switch and associated wiring into the Brake System Control Module. Conditions for Running the DTC Ignition OFF, ACCESSORY, or RUN mode. Conditions for Setting the DTC The Brake System Control Module detects an internal Parking Brake Control Switch malfunction. The Brake System Control Module detects if the apply or release button was activated for more than 90 s. Action Taken When the DTC Sets The parking brake is disabled. A message and/or a warning indicator may be displayed. Conditions for Clearing the DTC The Brake System Control Module will clear the DTC after 40 consecutive ignition on/off cycles with at least one test pass in each ignition cycle and no test fail result. The condition for the DTC is no longer present. The Park Brake Switch button is INACTIVE using the scan tool without the switch being activated. Reference Information Schematic Reference Park Brake System Schematics Connector End View Reference Master Electrical Component List Description and Operation Electronic Parking Brake Description 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 Verification

  1. Ignition ON.
  2. Verify the scan tool Park Brake Switch parameter changes between Inactive and Pressed while pressing and releasing the S91 Parking Brake Control Swtich. ⇒ If the parameter does not change Refer to Circuit/System Test. ⇓ If the parameter changes
  3. All OK. Circuit/System Test
  4. Ignition ON/Vehicle in Service Mode.
  5. Verify no other DTCs are set. ⇒ If any other DTCs are set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If no other DTCs are set
  6. Ignition OFF.
  7. Verify the S91 Parking Brake Control Swtich and any related wiring harnesses and connectors are securely connected and do not exhibit any physical damage, or that no foreign object is pressing on the switch. ⇒ If any damage is noted Repair as necessary. ⇓ If no damage is noted
  8. Program the K160 Brake System Control Module.
  9. Verify that the DTC does not set. ⇒ If the DTC sets Replace the S91 Parking Brake Control Swtich ⇓ If the DTC is not set
  10. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Parking Brake Control Switch Replacement Control Module References for module replacement, programming and setup.