C0281

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Part 2 Of 2:

CIRCUIT DESCRIPTION
The Stop Lamp Switch is normally closed. With the ignition in the RUN position and the brake pedal not depressed, the EBCM will have ignition voltage present at terminal C of the 10-way connector. When the brakes are applied, the ignition voltage present at terminal C of the EBCM will be zero.

CONDITIONS FOR SETTING THE DTC
^ After power-up, the microprocessor never sees the brake switch released and the vehicle reaches a speed above 56 km/h (35 mph), or
^ The vehicle is in an ABS stop for more than 2 seconds and the brake switch is not depressed

ACTION TAKEN WHEN THE DTC SETS
^ The ABS indicator lamp will not be illuminated
^ The ABS will not be disabled

DTC C0281 is advisory code only. The DTC is stored in memory, but the ABS indicator lamp will not light, and ABS will not be disabled.

CONDITIONS FOR CLEARING THE DTC
^ Repair the conditions responsible for setting the DTC
^ Use the Scan Tool Clear DTCs function.

DIAGNOSTIC AIDS
DTC C0281 can be set by a faulty Stop Lamp Switch, or damage in CKT 420 or CKT 441.
Thoroughly check any circuitry that is suspected of causing the intermittent complaint for the following conditions:
^ Backed out terminals
^ Improper mating
^ Broken locks
^ Improperly formed or damaged terminals
^ Poor terminal to wiring connections
^ Physical damage to the wiring harness

TEST DESCRIPTION
The numbers below refer to the steps in the diagnostic table:
2. Use the scan tool data list display to monitor the brake switch status.
4. This step will try to simulate an open stoplamp switch by removing the stoplamp switch connector.
5. This step decides between a short to voltage in CKT 420 and a malfunctioning EBCM.
6. This step eliminates an open CKT 420 as a possible cause.
7. Damage or corrosion to the EBCM 16-way harness connector terminals could be the cause for an intermittent DTC to set.