C0900

DTC C0900

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC C0900 07
- Device Voltage above Threshold

Diagnostic Fault Information





Circuit/System Description

The electronic brake control module (EBCM) monitors the ignition voltage. If the voltage level is too high, damage may result in the system. When a high voltage condition is detected the EBCM turns OFF the system relay which removes battery voltage from the solenoid valves and pump motor.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

The system voltage is greater than 16 volts for 100 msec.

Action Taken When the DTC Sets

* The traction control system (TCS) and vehicle stability enhancement system (VSES) are disabled for the duration of the ignition cycle.
* The ABS is disabled if ignition voltage exceeds 19.5 volts.
* The Stability System Off and Traction Control Off indicators illuminate.
* The antilock brake system (ABS) indicator illuminates if voltage exceeds 19.5 volts.

Conditions for Clearing the DTC

* The condition for the DTC is no longer present.
* The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Reference Information
Schematic Reference

Antilock Brake System Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

* ABS Description and Operation (with StabiliTrak) (ABS Description and Operation (with StabiliTrak))ABS Description and Operation (without StabiliTrak) (ABS Description and Operation (without StabiliTrak))
* Charging System Description and Operation (Description and Operation)

Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)

Diagnostic Aids

* A possible cause of this DTC could be overcharging with a battery charger or jump starting.
* A high voltage DTC in multiple modules indicates a concern in the charging system.

Circuit/System Verification

1. If the DTC is history, or if other modules also have high voltage DTCs stored, refer to Charging System Test (Charging System Test).
2. Start the engine, record the voltage at the battery terminals. Observe the scan tool Battery Voltage Signal parameter in the EBCM data list. Voltages should not differ by greater than 1 volt.

• If the difference is greater than 1 volt, replace the EBCM.

Repair Instructions

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

Control Module References (Programming and Relearning)for EBCM replacement, setup and programming.