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 C0899 00: Power Supply Circuit Low Voltage

### Circuit Description

The electronic brake control module (EBCM) monitors the voltage level available for system operation. A low voltage condition prevents the system from operating correctly.

### Conditions for Running the DTC

• | The ignition is ON.

• | The vehicle speed is greater than 8 km/h (5 mph).

### Conditions for Setting the DTC

One of the following conditions exists for 0.72 seconds:

• | During initialization or when the system is inactive, the system voltage is less than 9.6 volts.

• | During the system operation, the system voltage is less than 9.3 volts.

### Action Taken When the DTC Sets

• | The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS)/Electronic Stability Control (ESP)/Electronic Brake Distribution (EBD) for the duration of the ignition cycle.

• | The multi function display (MFD) displays the ABS Fault message.

• | The multi function display (MFD) displays the Traction Ctrl Off message.

• | The multi function display (MFD) displays the Stability Ctrl Off message.

### Conditions for Clearing the DTC

• | The condition for setting the DTC is no longer present.

• | The DTC can be cleared using a scan tool.

### Diagnostic Aids

• | Test the charging system. Refer to Charging System Test .

• | Possible causes of this DTC are the following conditions:

- | A charging system malfunction

- | Too much battery draw

- | A weak battery

- | A faulty system ground

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Verification

With scan tool installed, clear the DTCs then drive the vehicle in a straight line at a speed greater than 20 km/h (13 mph).

### Circuit/System Testing

1. Measure the voltage at the battery terminals.
2. With a scan tool, observe the Switched System Battery Voltage parameter in the ABS data list. Verify that battery terminal voltage and ignition voltage readings do not differ more than 1 volt.

⇒ | If more than 1 volt, test the ground circuit of the EBCM for high resistance. If the circuit test normal, test or replace the EBCM.

### Repair Instructions

• | Electronic Brake Control Module Replacement .

• | Control Module References