Engine Electrical

DTC C0900

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 Descriptor

DTC C0900

- Device Voltage High

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 is ON.

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.

Conditions for Clearing the DTC

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

Diagnostic Aids

Test the charging system.

Circuit/System Testing

1. Measure the voltage at the battery terminals.
2. Disconnect the EBCM harness connector.
3. With the ignition ON and the engine OFF, measure the voltage at the Run/Crank Ignition 1 Voltage circuit. Verify that battery terminal voltage and ignition voltage readings do not differ more than 1 volt.

• If more than 1 volt test the ignition voltage and ground circuits of the EBCM for high resistance, an open, or replace the EBCM.

4. Go to Charging System Test. Charging System Test

Repair Instructions

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

Control Module References for EBCM replacement, setup and programming