C0081

Stoplamp Switch Circuit Schematic:

DTC C0081 - Stoplamp Switch Always Closed Or Shorted:

CIRCUIT DESCRIPTION
The stoplamp switch is a normally closed switch. With the ignition in the RUN position and the brake pedal not depressed ignition voltage will be present at the Electronic Brake Control Module (EBCM). When the brakes are applied, the ignition voltage present at the EBCM will be zero.

CONDITIONS FOR SETTING THE DIAGNOSTIC TROUBLE CODE (DTC)
^ Vehicle speed above 35 mph for 10 seconds followed by vehicle at rest for 1 second
^ Stoplamp switch never switching during the above condition

ACTION TAKEN WHEN THE DTC SETS
^ ANTILOCK indicator lamp is illuminated
^ Antilock Brake System (ABS) is disabled

NOTE: This DTC is an Ignition Latched DTC, which indicates that the above is true until the ignition switch is turned to Off position (even if the cause of the DTC is intermittent).

DIAGNOSTIC AIDS
A faulty stoplamp switch or circuit condition in circuit 420 can cause this DTC.

TEST DESCRIPTION

NOTE: Number(s) below refer to number(s) on the diagnostic chart.

2. Check stoplamp switch status using the scan tool.
3. Check for a short to battery or improperly adjusted stoplamp switch.
5. Check for an open in circuit 420 or faulty stoplamp switch.