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

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
B+ | C0899 | C0899 | -- | --
Ground | -- | C0899 | -- | --

### 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 V 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 V.

• | The TCS indicator turns ON.

• | The Antilock Brake System (ABS) indicator turns ON if voltage exceeds 19.5 V.

• | 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.

### 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.

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

ABS Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information.

### Circuit/System Verification

1. Engine running measure and record the voltage at the battery terminals. Verify that the battery voltage is 12.6-15.5 V.

⇒ | If the battery voltage is not within the specified range, refer to Charging System Test

2. Engine running, observe the scan tool EBCM battery positive voltage parameter. The reading should be between 12.6 and 15.5 V.

⇒ | If not within the specified range, replace the EBCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup and programming.