C1291

CIRCUIT DESCRIPTION
This circuit is used to detect an open Stoplamp switch in the non-Antilock Brake System (ABS) mode. The Electronic Brake and Traction Control Module (EBTCM) looks for a deceleration rate that would indicate braking action and verifies this assumption by requiring several repeats of this detection method. In each case, Traction Control System (TCS)/Active Handling (if equipped with RPO JL4) will not be available since no Stoplamp switch voltage is seen by the EBTCM.

CONDITIONS FOR SETTING THE DTC
DTC C1291 is set after the Stoplamp switch remains open for three deceleration cycles.

ACTION TAKEN WHEN THE DTC SETS
Antilock Brake System (ABS) remains enabled, Traction Control System (TCS)/Active Handling (if equipped with RPO JL4) are disabled.
^ Indicators that turn on:
- Car Icon (TCS indicator)
^ Messages displayed on the Driver Information Center (DIC):
- Service Traction System
- Service Active HNDLG (if equipped with RPO JL4)

CONDITIONS FOR CLEARING THE DTC
^ Condition for Diagnostic Trouble Code (DTC) is no longer present and Scan tool clear DTC function is used.
^ Fifty ignition cycles have passed with no DTCs detected.

DIAGNOSTIC AIDS
^ It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
^ If any Wheel Speed Sensor Diagnostic Trouble Codes (DTCs) are present you must diagnose them first.
^ An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation.
^ If an intermittent malfunction exists refer to Testing for Electrical Intermittents in Diagnostic Aids.
^ Possible causes:
- Open Stoplamp switch.
- Open fuse.
- Stoplamp switch misadjusted.
- Erratic Wheel Speeds.
- Circuit has a wiring problem, terminal corrosion, or poor connections.

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
3. Checks if Stoplamp switch and power distribution are OK.
4. Checks for voltage at Electronic Brake and Traction Control Module (EBTCM).
10. Checks the Stoplamp switch.

Part 1 Of 2:

Part 2 Of 2:

DTC C1291 OPEN BRAKE LAMP SWITCH CONTACTS DURING DECELERATION