For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using the 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

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
EBCM battery Voltage High | -- | -- | -- | C0900 00

### Circuit/System Description

The electronic brake control module (EBCM) monitors the battery 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 17 volts for 1 msec.

### Action Taken When the DTC Sets

• | ABS/EBD/Engine Traction System (ETS) disabled for the duration of the ignition cycle.

• | ABS disabled if battery voltage exceeds 17 volts.

• | The Antilock Brake System (ABS) indicator/Engine Traction (ETS)/Brake Warning Lamp turns ON if voltage exceeds 17 volts.

### 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

#### 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