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 Below ThresholdDTC C0890 07 : Device Voltage Reference Output 3 Circuit Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | Open or High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Brake Position Sensor Signal | C0277 06 | C0277 06 | C0277 07 | C0277 09, C0277 4B |
5-Volt Reference | C0277 06, C0890 03 | C0277 06 | C0277 07, 1 | -- |
Low Reference | -- | C0277 07, 1 | -- | -- |
1. Stop lamps are always ON | ||||
Circuit/System Description
The body control module (BCM) provides a 5-volt reference voltage and a low reference signal to the brake pedal position sensor (BPPS). When the brake pedal is applied, the BPPS sends a variable voltage signal, that will increase as the brake pedal is applied, through the stop lamp switch signal circuit to the BCM. In response to this signal, the BCM applies battery positive voltage to the stop lamps, center high mounted stop lamp (CHMSL), transmission control module (TCM), and engine control module (ECM). The stop lamps will not operate unless the ignition is in the ON position.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
C0890 03
This DTC will set when the BCM detects a short to ground in the brake pedal position sensor voltage reference circuit for 0.5 second or greater.
C0890 07
This DTC will set when the BCM detects a short to battery voltage in the brake pedal position sensor voltage reference circuits for 0.5 second or greater.
Action 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. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Diagnostic Aids
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 Verification
Ignition ON, press and release the brake pedal. The stop lamps should turn ON and OFF when pressing and releasing the brake pedal.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
- Verify that a test lamp illuminates between the low reference circuit terminal C and B+.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground.
- If all circuits test normal, replace the brake pedal position sensor.
| ⇒ | If the test lamp does not illuminate, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | 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/connections test normal, replace the BCM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit test normal, replace the BCM. |
Repair Instructions
Important: Perform the Brake Pedal Position Sensor Calibration after replacement of the brake pedal position sensor.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
