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 Descriptors
DTC C0890 03: Device Voltage Reference Output 3 Circuit Voltage Below ThresholdDTC C0890 07: Device Voltage Reference Output 3 Circuit Voltage Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Body Control Module (BCM) 5 Fuse B+ Supply | 1, 2 | 1, 2 | -- | -- |
Body Control Module (BCM) 6 Fuse B+ Supply | 1, 2 | 1, 2 | -- | -- |
Center High Mounted Stop Lamp (CHMSL) Control | B3445 00 | 2 | 2 | -- |
Brake Position Sensor Signal | C0277 06, 07 | C0277 06 | C0277 07 | C0277 09 |
Stop Lamp Relay Control - Export | B3445 00 | 2 | 2 | -- |
Stop Lamp Relay Switch B+ - Export | 2 | 2 | -- | -- |
Brake Position Sensor 5-Volt Reference | C0277 06, C0890 03 | C0277 06, C0890 03 | 1, 2 | -- |
Brake Position Sensor Low Reference | -- | C0277 06 | 1, 2 | -- |
Left Rear Stop/Turn Lamp Supply Voltage | 1, 2 | 1, 2 | 1, 2 | -- |
Right Rear Stop/Turn Lamp Supply Voltage | 1, 2 | 1, 2 | 1, 2 | -- |
Center High Mounted Stop Lamp (CHMSL) Ground | -- | 1, 2 | 1, 2 | -- |
Left Rear Stop/Turn Lamp Ground | -- | 1, 2 | 1, 2 | -- |
Right Rear Stop/Turn Lamp Ground | -- | 1, 2 | 1, 2 | -- |
Stop Lamp Relay Ground - Export | -- | 2 | 2 | -- |
| ||||
Circuit/System Description
Domestic
The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL) control circuit. For more detailed information concerning stop lamp operation refer to Exterior Lighting Systems Description and Operation .
Export
The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay coil side control circuit, transmission control module (TCM), engine control module (ECM), and 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 from the STOP LAMPS fuse to illuminate the rear stop lamps and trailer stop lamps. For more detailed information concerning stop lamp operation refer to Exterior Lighting Systems Description and Operation .
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
C0890 03
The DTC will set when the BCM detects a short to ground in the brake pedal position sensor voltage reference circuit for 0.5 seconds or greater.
C0890 07
The DTC will set when the BCM detects a short to battery voltage in the brake pedal position sensor voltage reference circuits for 0.5 seconds or greater.
Actions Taken When the DTC Sets
| • | The Service Vehicle Soon indicator is commanded ON. |
| • | If the DTC sets while the vehicle is running, the BCM will activate the brake lights when the vehicles transmission is not in the PARK position and the vehicle is not accelerating. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | You issue a scan tool CLEAR DTCs command. |
| • | A history DTC will clear once 50 malfunction-free ignition cycles have occurred. |
| • | A DTC will not clear the current status until the next ignition cycle. |
Diagnostic Aids
Important: The stop lamps will not illuminate unless the ignition is in the ON position. For more detailed information concerning stop lamp operation, refer to Exterior Lighting Systems Description and Operation .
Reference Information
Schematic Reference
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
- Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal B.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
- If all circuits test normal, test or replace the brake pedal position sensor.
| ⇒ | If the test lamp does not illuminate, test the low reference circuit for an open/high resistance. |
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. 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 |
