B3445

DTC B3445

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC B3445 00
- Stop Lamp Circuit




Diagnostic Fault Information






Circuit/System Description

Battery voltage is applied at all times to the body control module (BCM) from the BACKUP/STOP fuse located in the I/P fuse block. When the brake pedal is applied and the BCM receives a brake applied signal from the brake pedal position sensor (BPPS). It then applies battery voltage from the BACKUP/STOP fuse through the CHMSL control circuit to the CHMSL.


Conditions for Running the DTC

* Ignition ON.
* The stop lamps must be commanded ON.



Conditions for Setting the DTC

The BCM detects a short to ground on the CHMSL control circuit when the stop lamps are being commanded ON.


Action Taken When the DTC Sets

The CHMSL does not illuminate.


Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.



Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the CHMSL.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal 2 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal 1 and ground.
4. Ignition ON, press and release the brake pedal. The test lamp should turn ON and OFF when pressing and releasing the brake pedal.

• 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.

5. If all circuits test normal, test or replace the CHMSL.



Repair Instructions

Perform theDiagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* High Mount Stop Lamp Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming