Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | 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 VoltageDiagnostic Fault Information
Circuit | Short to Ground | Open or High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Brake Applied Signal | P0572 00 | P0572 00 C0297 00 | P0573 00 C0297 00 | -- |
Circuit/System Description
The brake applied signal circuit is a direct hardwire input from the body control module (BCM) to the engine control module (ECM) and transmission control module (TCM). The ECM monitors the brake applied signal 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 sends a voltage signal on the brake applied signal circuit to the ECM and TCM.
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 a high voltage signal either when the brakes are applied or unapplied.
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. |
| • | A history DTC will clear once 40 malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Connector End View Reference
Cruise Control Connector End Views
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector C1 at the ECM and the harness connector at the TCM.
- Ignition ON, test for 0 volts between the signal circuit ECM connector C1 terminal 7 (LZ9) or terminal 9 (LZ4) or terminal 55 (L61) and ground.
- Ignition OFF, connect the harness connector at the TCM.
- Ignition ON, test for 0 volts between the signal circuit ECM connector C1 terminal 7 (LZ9) or terminal 9 (LZ4) or terminal 55 (L61) and ground.
- If all circuits test normal, replace the ECM.
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If greater than the specified range, replace the TCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM, BCM or TCM replacement, setup, and programming
