P0571

DTC P0571

CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to the powertrain control module (PCM). When the PCM receives this signal, it cancels the cruise control.

When the stop light switch is ON, the battery positive voltage is applied through the STOP fuse and stop light switch to the PCM.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
Stop light switch does not turn OFF when the vehicle is being driven.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the malfunction indicator lamp (MIL) the first time the diagnostic runs with the fault active.
- The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

CONDITIONS FOR CLEARING THE MIL/DTC
- The MIL turns OFF after 3 consecutively passing trips without a fault present.
- A History DTC clears after 40 consecutive warm-up cycles without a fault.
- Use the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
A scan tool should indicate the state of the stop light switch.

An intermittent malfunction may be caused by a fault in the stop lamp electrical circuit. Inspect the wiring harness and the components for any of the following conditions:
- Any backed-out terminals
- Any improper mating of terminals
- Any broken electrical connector locks
- Any improperly formed or damaged terminals
- Any faulty terminal-to-wire connections
- Any physical damage to the wiring harness
- A broken wire inside the insulation
- Any corrosion of the electrical connections, the splices, or the terminals

Repair any electrical circuit faults that were found.

TEST DESCRIPTION

Steps 1 - 10:

Steps 11 - 13:

The numbers below refer to the step numbers in the diagnostic table.
2. This step monitors the state of the stop lamp switch as detected by the PCM.
4. This step checks continuity of the stop lamp switch internal contacts.
6. This step checks for battery positive voltage at the stop lamp switch.
7. This step checks the state of the stop lamp switch input to the PCM.