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 |
|---|---|---|---|---|
Center High Mounted Stop Lamp (CHMSL) Control | B3445 00 | 1 | 1 | -- |
Ground | -- | 1 | -- | -- |
1. Stop Lamps Malfunction | ||||
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
| • | 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 CHMSL control circuit when the stop lamps are being commanded ON.
Action Taken When the DTC Sets
The BCM will not illuminate the CHMSL.
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
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 harness connector at the CHMSL.
- Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
- Connect a test lamp between the control circuit terminal A and ground.
- 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 all circuits test normal, test or replace the CHMSL.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
