C1291

DTC C1291 Open Brake Lamp Switch Contacts During Deceleration - Part 1 Of 2:

DTC C1291 Open Brake Lamp Switch Contacts During Deceleration - Part 2 Of 2:

CIRCUIT DESCRIPTION
This circuit detects an open stoplamp/BTSI switch in the non-ABS mode. The EBTCM looks for a deceleration rate that indicates braking action and requires several repeats of this detection method in order to verify this assumption. In each case, the TCS will not be available since the EBTCM detects no stoplamp/BTSI switch voltage.

CONDITIONS FOR SETTING THE DTC
^ The stoplamp/BTSI switch remains open for 3 deceleration cycles.
^ The DTC is set in the current or previous ignition cycle.

ACTION TAKEN WITH THE DTC SETS
^ A malfunction DTC is stored.
^ The TCS is disabled.
^ The TRACTION CONTROL indicator is turned ON.
^ The ABS remains functional.

CONDITIONS FOR CLEARING THE DTC
^ The condition for DTC is no longer present and you used scan tool Clear DTCs function.
^ The condition for DTC is no longer present and you used the On-Board Clear DTCs function.
^ The EBTCM does not detect the DTC in 50 drive cycles.

DIAGNOSTIC AIDS
^ If any wheel speed sensor DTCs are present, diagnose them first. Refer to DTC List.
^ Thoroughly inspect the wiring and the connectors. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis. Misdiagnosis may cause part replacement with reappearance of the malfunction.
^ The following conditions may cause an intermittent malfunction:
^ A poor connection
^ Broken insulation
^ Broken wire inside the insulation
^ If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Diagnostic Aids.
^ This DTC may be caused by one of the following:
- An open stoplamp/BTSI switch
- An open rear junction block STOP LID Fuse
- The stoplamp/BTSI switch is 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 the stoplamp/BTSI switch and power distribution are functional.
4. Checks for voltage at EBTCM.
10. Checks the stoplamp/BTSI switch.