Engine Electrical

DTC C0900

Diagnostic Instructions

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



DTC Descriptor
DTC C0900
- Device Voltage High




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

Engine running.


Conditions for Setting the DTC

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


Action Taken When the DTC Sets

* Traction Control System (TCS) and Vehicle Stability Enhancement System (VSES) disabled for the duration of the ignition cycle.
* ABS disabled if ignition voltage exceeds 19.5 volts.
* The TCS indicator turns ON.
* The Antilock Brake System (ABS) indicator turns ON if voltage exceeds 19.5 volts.
* The driver information center (DIC) displays the Service Stability System message, if equipped.



Conditions for Clearing the DTC

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



Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information.


Diagnostic Aids

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



Circuit/System Verification

1. Verify DTC C0900 is set as current.

• If the DTC is history, refer to Charging System Test (Charging System Test) .

2. Start the engine, record the voltage at the battery terminals. Observe the scan tool EBCM battery voltage signal parameter. Voltages should not differ by more than 2 volts

• If not within the specified range, 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.