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 B3445 00: Stop Lamp CircuitDiagnostic 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 DTC will set when the BCM detects a short to ground in the stop lamp control circuit when the stop lamps are being commanded ON. |
| • | The DTC will set when the BCM detects a short to ground or an open/high resistance in the STOP fuse B+ circuit terminal 4 X4. |
Actions Taken When the DTC Sets
The BCM will not illuminate the stop lamps.
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
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the X4 harness connector at the BCM.
- Verify that a test lamp illuminates between the STOP fuse B+ circuit terminal 4 and ground.
- Connect the X4 harness connector at the BCM.
- Disconnect the harness connectors at the following components.
- Connect a test lamp between the control circuit terminal 4 at the tail/stop lamp - right and ground.
- Ignition ON, command the Brake Light Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- Reconnect each component one at a time and verify the DTC does not reset as current.
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
| • | CHMSL |
| • | Tail/stop lamp - left |
| • | Tail/stop lamp - right |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If the DTC resets as current, test or replace the component responsible for setting the DTC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
