B3445

DTC B3445

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 Circuit

Diagnostic Fault Information






Circuit/System Description

Battery voltage is applied at all times to the body control module (BCM) from the BCK/UP/STOP Fuse located in the rear 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 BCK/UP/STOP fuse through the CHMSL voltage supply circuit to the CHMSL.

Conditions for Running the DTC

* The ignition is ON.
* The stop lamps must be commanded ON.

Conditions for Setting the DTC

The BCM detects a short to ground on the CHMSL voltage supply 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.

Circuit/System Testing

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

* RPO W49 - terminal A
* RPO WDA/Z88 - terminal 1

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

3. Connect a test lamp between the supply voltage circuit terminal listed below and ground:

* RPO W49 - terminal B
* RPO WDA/Z88 - terminal 2

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 voltage supply circuit for a short to voltage. If the circuit tests normal, replace the BCM.
^ If the test lamp is always OFF, test the voltage supply 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 the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* High Mount Stop Lamp Replacement (Acadia) High Mount Stop Lamp Replacement (Enclave) High Mount Stop Lamp Replacement (OUTLOOK)