• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Stop Lamp Relay Switch B+ | 1 | 1 | -- | -- |
Stop Lamp Switch B+ Voltage Reference | B1395 03, B3600 03 | 1 | 1 | -- |
Stop Lamp Switch Signal | 1 | 1 | 1 | -- |
Stop Lamp Relay Control | B3445 00 | 1 | 1 | -- |
Tail/Stop Lamp Control - Left | 1 | 1 | 1 | -- |
Tail/Stop Lamp Control - Right | 1 | 1 | 1 | -- |
Center High Mounted Stop Lamp (CHMSL) Ground | -- | 2 | -- | -- |
Tail/Stop Lamp Ground - Left | -- | 1 | -- | -- |
Tail/Stop Lamp Ground - Right | -- | 1 | -- | -- |
Stop Lamp Relay Ground | -- | 1 | -- | -- |
1. Stop Lamps Malfunction 2. Center High Mounted Stop Lamp (CHMSL) Malfunction |
The stop lamp switch is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides a low reference signal and a B+ reference voltage to the stop lamp switch. When the stop lamp switch contacts close indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay control circuit and the center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage to the STOP LAMPS fuse to illuminate the left and right stop lamps.
• | Battery voltage must be between 9-16 volts. |
• | Brakes APPLIED. |
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.
The BCM will not illuminate the CHMSL.
• | The condition responsible for setting the DTC no longer exists. |
• | A history DTC will clear once 100 malfunction-free ignition cycles have occurred. |
Exterior Lighting Systems Description and Operation
• | Circuit Testing |
• | Wiring Repairs |
Control Module References for scan tool information
⇒ | 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. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |