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 C0297 00: Brake Applied Output Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
BCM B+ Terminal 4 X4 | B3445 00 | B3445 00 | -- | --
Brake Pedal Position Sensor 5-Volt Reference | C0277 06, C0890 03, C0161 71 | C0277 06, C0161 71 | C0277 07, C0161 71 | --
Brake Applied Signal Terminal 6 X5 | C0297 00, P0571 00 | 3 | 3 | --
Brake Pedal Position Sensor Signal | C0277 06, C0161 71 | C0277 06, C0161 71 | C0277 07, C0161 71 | C0277 09
Stop Lamp Control | B3445 00 | 1 | 1 | --
Brake Position Sensor Low Reference | -- | 1 | 1 | --
Center High Mounted Stop Lamp (CHMSL) Ground | -- | 2 | -- | --
Left Rear Tail/Stop Lamp Ground | -- | 1 | -- | --
Right Rear Tail/Stop Lamp Ground | -- | 1 | -- | --
1. Stop Lamps Malfunction 2. Center High Mounted Stop Lamp (CHMSL) Malfunction 3. Cruise Control Malfunction

### Circuit/System Description

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the stop lamp control circuit illuminating the left and right stop lamps and the center high mounted stop lamp (CHMSL). The BCM also applies battery voltage to the transmission control module (TCM) and engine control module (ECM) via the brake applied signal circuit.

### Conditions for Running the DTC

• | Battery voltage must be between 9-16 volts.

• | Brakes APPLIED.

### Conditions for Setting the DTC

The BCM detects a short to ground in the brake applied signal circuit.

### Actions Taken When the DTC Sets

The Service Vehicle Soon indicator is commanded ON.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

### Reference Information

#### Schematic Reference

Exterior Lights Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exterior Lighting Systems Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

1. Ignition OFF, disconnect the appropriate harness connector listed below.

• | ECM X1 - with L76

• | ECM X2 - with LY7

2. Connect a test lamp between the apprpriate signal circuit terminal listed below and ground.

• | ECM terminal 9 X1 - with L76

• | ECM terminal 52 X2 - with LY7

3. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.

⇒ | If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

4. Ignition OFF, connect a test lamp between the appropriate signal circuit terminal listed below at the ECM harness connector and the connector terminal at the ECM.

• | ECM terminal 9 X1 - with L76

• | ECM terminal 52 X2 - with LY7

5. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp does not turn ON and OFF when commanded, replace the ECM.

6. Ignition OFF, connect the harness connector at the ECM.
7. Disconnect the harness connector at the TCM.
8. Connect a test lamp between the appropriate signal circuit terminal listed below and ground.

• | TCM terminal 42 - with 4L60E/4L65E

• | TCM terminal 38 - with 5L40E

• | Automatic transmission terminal 6 - 6L50E

9. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.

⇒ | If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

10. If all circuits test normal, replace the TCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Brake Pedal Position Sensor Calibration

• | Control Module References for BCM, ECM, or TCM replacement, setup, and programming