C1291

DTC C1291: Open Brake Lamp Switch Circuit During Deceleration (Part 1 Of 2):

DTC C1291: Open Brake Lamp Switch Circuit During Deceleration (Part 2 Of 2):

DTC C1291 Schematic:

CIRCUIT DESCRIPTION
This circuit is used to detect an open brake switch in the non-ABS mode. The Electronic Brake/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, TCS will not be available since no brake stoplamp/Brake Transaxle Shift Interlock (BTSI) voltage is seen by the EBTCM.

CONDITION FOR SETTING THE DTC
Diagnostic Trouble Code (DTC) C1291 is set after the Brake Switch remains open for three deceleration cycles.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, TCS is disabled and the TRACTION OFF indicator lamp is turned ON. ABS remains functional.

CONDITIONS FOR CLEARING THE DTC
Condition for DTC is no longer present and scan tool clear function is used. Fifty start 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 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. Possible causes: Open stoplamp/BTSI switch. Open brake fuse. Stoplamp/BTSI 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/BTSI switch and power distribution are OK.
[4] Checks for voltage at the EBTCM.
[10] Checks stoplamp/BTSI switch.