• 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.

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP sensor provides an analog voltage signal that will increase as the brake pedal is applied. The K9 Body Control Module (BCM) and K20 Engine Control Module (ECM) both provide a low reference, signal, and a 5 V reference voltage to the BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to circuit 6311 as a redundant brake apply signal to the ECM. The ECM responds to the multiple brake applied signals by disabling cruise control.

• Battery voltage must be between 9–16 V.
• Brakes APPLIED.

The BCM detects a short to ground or an open/high resistance on the brake applied signal circuit.

The cruise control system is disabled.

• The condition responsible for setting the DTC no longer exists.
• A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Verify that the brake pedal position sensor is properly calibrated prior to circuit/system testing. Refer to Brake Pedal Position Sensor Calibration.

Cruise Control Schematics

Master Electrical Component List

Exterior Lighting Systems Description and Operation

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Control Module References for scan tool information

1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Connect a test lamp between the appropriate signal circuit terminal listed below and ground, ignition ON.
• {LTG/LYX} Terminal 50
• {LH7} Terminal 23
3. Verify the test lamp turns ON and OFF while pressing and releasing the brake pedal.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K9 Body Control Module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K9 Body Control Module.
• If the test lamp turns ON and OFF
4. Replace the K20 Engine Control Module.

Perform the Diagnostic Repair Verification after completing the repair.

• Brake Pedal Position Sensor Calibration
• Control Module References for BCM or ECM replacement, programming, and setup