GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Lucerne 🢒 Vehicle Control Systems 🢒 Computer/Integrating Systems 🢒 DTC B3445

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 Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

CHMSL Voltage Supply

B3445 00

1

2

--

Ground

--

1

--

--

  1. Stop Lamps Inoperative
  2. Stop Lamps Always On

Circuit/System Description

Battery voltage is applied at all times to the body control module (BCM) from the CHMSL/BCK-UP 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 CHMSL/BCK-UP 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.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

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 B and ground.
    3. ⇒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 A 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.
    5. ⇒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.

    •  High Mount Stop Lamp Replacement
    •  Control Module References for BCM replacement, setup, and programming