C0890

DTC C0890

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 Threshold

DTC C0890 07
- Device Voltage Reference Output 3 Circuit Above Threshold

Diagnostic Fault Information






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.

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

1. Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
2. Verify that a test lamp illuminates between the low reference circuit terminal C and B+.

^ 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.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground.

^ 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.

4. If all circuits test normal, replace the brake pedal position sensor.

Repair Instructions

Important: Perform the Brake Pedal Position Sensor Calibration after replacement of the brake pedal position sensor. Programming and Relearning

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Brake Pedal Position Sensor Replacement.