For 1990-2009 cars

### 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 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.

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Antilock Brake System Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

### 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. If the DTC is history, refer to Charging System Test .
2. Start the engine. Record the voltage at the battery terminals. Observe the battery voltage signal parameter in the EBCM data list. Voltages should not differ by more than 1 volt.

⇒ | If more than 1 volt, replace the EBCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup and programming