P0573

DTC P0573

Diagnostic Instructions
^ Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure. Diagnostic System Check - Vehicle Diagnostic Information
^ Review [Strategy Based Diagnosis] for an overview of the diagnostic approach. Strategy Based Diagnosis
^ [Diagnostic Procedure Instructions - Vehicle Diagnostic Information] provides an overview of each diagnostic category. Diagnostic Procedure Instructions - Vehicle Diagnostic Information

DTC Descriptor
DTC P0573 Brake Switch Circuit 1 High Voltage.

Diagnostic Fault Information






Circuit/System Description
The brake pedal position sensor (BPP) is used to sense the action of the driver application of the brake pedal. The BPP provides an analog voltage signal that will increase as the brake pedal is applied. The BPP 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 BPP 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
Verify that the BPP is properly calibrated.

Circuit/System Testing
1. With a scan tool, recalibrate the BPP, 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
Perform the [Diagnostic Repair Verification - Vehicle Diagnostic Information] after completing the diagnostic procedure. Diagnostic Repair Verification - Vehicle Diagnostic Information
^ Brake Pedal Position Sensor Replacement]
^ [Control Module References] for ECM replacement, setup, and programming Programming and Relearning
^ [Brake Pedal Position Sensor Calibration]