C1291

DTC C1291 (1 Of 2):

DTC C1291 (2 Of 2):

CIRCUIT DESCRIPTION
This DTC is used to detect an open stoplamp switch in the non-ABS mode. The EBCM looks for deceleration rates that would indicate braking action and verifies this assumption by requiring several repeats of this detection method. In each case, ABS will not be available because stoplamp switch input is not seen by the EBCM.

CONDITIONS FOR SETTING THE DTC
DTC C1291 can be set if three deceleration cycles within the specified rate occur during the current ignition cycle with the brake switch off.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS is disabled, and the amber ABS warning indicator is turned on.

DIAGNOSTIC AIDS
An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. The frequency of the malfunction can be checked by using the enhanced diagnostic function of the scan tool. Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections, or physical damage to the wiring harness.

NOTE: J 39200 test leads must be zeroed prior to making any resistance measurements.