Antilock Braking System (ABS)

Diagnostic Chart:

Circuit Diagram:

STOP LAMP CIRCUIT OPEN
The brake switch circuit which activates the ABS control module is shared by the stop lamps and center high mounted stop lamp (CHMSL). If all the bulbs (four stop lamps and rear window stop lamp) are open, or the ground is open, or circuit 20 is open, the brake switch circuit to the ABS control module will be pulled high. ABS will be disabled and the antilock telltale will be turned On.

CODE PARAMETERS

Code 95 sets if:
^ Stop lamp circuit is open.
^ Circuit 20 is open.
^ This code will fail at all times. If this code fails during an ABS stop, it may also fail code 92.
^ This code may also fail in conjunction with code 96.

DIAGNOSTIC AIDS
When attempting to diagnose an intermittent problem, use the Scan tool[1] to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem.


Intermittents or opens suspected to be at the connectors can be detected by using a diagnostic service probe. Voltage can be read on wires without disconnecting any connectors.
Check the tightness of the female terminal grip with a spare male terminal.

Brake switch is normally open. Depressing brake pedal completes (closes switch) the circuit.

[1] Select Malfunction History from Scan tool ABS menu.