Cruise Control

DTC P0573

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0573 00
- Brake Switch Circuit 1 High Voltage

Diagnostic Fault Information






Circuit/System Description

The stop lamp switch signal circuit is a direct hardwire input to the engine control module (ECM) from the body control module (BCM). The ECM monitors the stop lamp switch circuit to detect when the brake pedal has been applied. The BCM monitors the brake pedal position (BPP) sensor to determine when the brake pedal is applied. When the brake pedal is applied, The BCM sends a GMLAN serial data message to the ECM indicating that the brake pedal has been applied. The BCM also sends a voltage signal on the stop lamp switch circuit to the ECM.

Conditions for Running the DTC

* The ignition is ON.
* The engine is running.
* Battery voltage is greater than 11.5 volts.

Conditions for Setting the DTC

The ECM detects an open, a high resistance or a 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.
* The ECM receives a CLEAR DTCs command from the scan tool.
* A history DTC will clear once 40 malfunction-free ignition cycles have occurred.

Circuit/System Testing

Test the stop lamp switch signal circuit for an open/high resistance, or a short to voltage.

If the circuit tests OK, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Refer to Programming and Relearning for ECM setup and programming. Programming and Relearning