DTC A094: Stoplamp Switch Contacts Always Closed

STOPLAMP SWITCH CONTACTS ALWAYS CLOSED





Circuit Description
This DTC is run to determine the proper operation of the stoplamp switch. This is important because ABS is activated when the stoplamp switch is closed and deactivated when the switch is open. If the stoplamp switch is always closed, ABS operation will always be requested, resulting in potential hydraulic modulator cycling on rough roads. Additionally, this malfunction will most likely result in a discharged battery (due to the stoplamps remaining on) if the driver is not informed of the problem.

Diagnosis
This test checks if the stoplamp switch input is seen at ignition ON and remains on for the rest of the drive cycle until the vehicle reaches 40 km/h (25 mph) for two consecutive drive cycles.

Cause(s)
- The stoplamp switch contacts are misadjusted or shorted.
- There is a short to voltage in the stoplamp switch circuitry.
- The electronic brake control module (EBCM) is faulty.

Fail Action
Set history code.

Test Description
The number(s) below refer to step(s) on the diagnostic table.
1. This checks if the malfunction is currently present.
2. This step checks for unwanted voltage on the stoplamp switch input circuit.
3. This step checks for a possible intermittent malfunction.
8. This step traces the cause of the malfunction to either a malfunctioning or misadjusted stoplamp switch or a short to voltage in the stoplamp switch circuitry.

Diagnostic Aids
An intermittent malfunction may be caused by a poor connection, wire insulation that has been rubbed through, or a wire that is broken inside the insulation.
Check the frequency of the malfunction by using the enhanced diagnostic feature of the scan tool as described in "Scan Tool Diagnostics." Scan Tool Diagnostics
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.





DTC A094 - Stoplamp Switch Contacts Always Closed