Antilock Braking System (ABS) - Four Wheel Antilock Brakes (4WAL)

DIAGNOSTIC TROUBLE CODE 81

BRAKE SWITCH CIRCUIT OPEN OR SHORTED

CIRCUIT DESCRIPTION:

A DTC 81 relates to the EBCM not seeing the brake switch signal from start up until 10 seconds after the vehicle reaches speeds over 56 km/h (35 mph). An indication of an open brake switch circuit is the "ANTILOCK" lamp will turn on during acceleration at 24 km/h (15 mph) and turn off during deceleration at 24 km/h (15 mph). A faulty brake switch or circuit condition in CKT 420 can cause this DTC.

Important
- Do not replace the EBCM for this DTC. A faulty EBCM will not cause this DTC to set.

TEST DESCRIPTION:

- Check for a blown "BRAKE" fuse.
- Check brake switch status using the Scan Tool.
- Check CKT 420 for looseness or corrosion.

DIAGNOSTIC AIDS:

This DTC could be caused by the driver riding the brake pedal.

This DTC is a soft fault. The "ANTILOCK" lamp will not turn on until the vehicle reaches 24 km/h (15 mph).

Do not pierce the electrical connectors, wires, seals, or insulation during testing. Doing so will break the seal and lead to corrosion and failure of the wiring and terminals.