P0573

DTC P0573

DTC DESCRIPTOR

DTC P0573: Brake Switch Circuit 1 High Voltage




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The brake pedal position sensor (BPPS) is used to sense the action of the driver application of the brake pedal. The BPPS provides an analog voltage signal that will increase as the brake pedal is applied. The BPPS receives a low reference signal and a 5-volt reference voltage from the body control module (BCM) when the driver applies the brakes. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the stop/turn signal voltage supply circuit to illuminate the stop lamps and the center high mounted stop lamp (CHMSL). The BCM also sends a BPPS signal to the engine control module (ECM) as well as a serial data message to indicate the application of the brake pedal.

CONDITIONS FOR RUNNING THE DTC
- The ignition is ON.
- Battery voltage is greater than 11.5 volts.

CONDITIONS FOR SETTING THE DTC
The ECM detects an open or short to voltage on the stop lamp switch signal circuit when the serial data message from the BCM indicates the brakes are applied.

ACTION TAKEN WHEN THE DTC SETS
- The ECM stores the DTC to memory.
- The ECM will record the operating conditions at the time the diagnostic failed. The ECM stores this information in Failure Records.

CONDITIONS FOR CLEARING THE DTC
- The condition responsible for setting the DTC no longer exists.
- You issue a scan tool CLEAR DTCs command.
- A history DTC will clear once 40 malfunction-free ignition cycles have occurred.

DIAGNOSTIC AIDS

IMPORTANT: Verify that the BPPS is properly calibrated.

CIRCUIT/SYSTEM TESTING
1. With a scan tool, recalibrate the BPPS, clear all DTCs, and operate the vehicle within the Conditions for Running the DTC.
- If DTC P0573 resets as current, test the stop lamp switch signal circuit for an open or short to voltage.
2. If circuits test OK, replace the ECM.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Control Module References for ECM replacement, setup, and programming
- Brake Pedal Position Sensor Calibration