For 1990-2009 cars

### 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 P0575 00: Cruise Control Switch Signal Circuit

### Circuit/System Description

When a cruise control function switch is activated, the body control module (BCM) detects a predetermined voltage signal. The BCM sends a GMLAN serial data message to the engine control module (ECM) indicating the function that has been requested.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

• | The ECM receives an invalid cruise control switch status GMLAN serial data message from the BCM.

• | This diagnostic runs continuously.

### Action Taken When the DTC Sets

• | The Cruise Control System is disabled.

• | The ECM stores the DTC information into memory when the diagnostic runs and fails.

• | The malfunction indicator lamp (MIL) will not illuminate.

• | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.

• | All cruise control function switches are set to OFF.

### Conditions for Clearing the DTC

• | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.

• | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.

• | Use the scan tool in order to clear the DTC.

### Diagnostic Aids

• | This DTC may be stored as a history DTC without affecting the operation of the BCM. If stored only as a history DTC and not retrieved as a current DTC, do not replace the BCM or ECM.

• | If this DTC is retrieved as both a current and history DTC, replace the BCM.

• | Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

### Reference Information

#### Schematic Reference

Cruise Control Schematics

#### Connector End View Reference

Data Communication Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Scan Tool Data List

### Circuit/System Verification

Ignition ON, observe the scan tool Cruise Control Switch parameter while pressing the cruise control switch ON and OFF. The reading should change between ON and OFF.

### Circuit/System Testing

Ignition ON, verify that DTC P0575 is stored in the ECM.

⇒ | If the DTC is stored as a current DTC, replace the ECM.

⇒ | If the DTC is stored only as a history DTC, refer to Diagnostic Aids. Do not replace the ECM or BCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming