For 1990-2009 cars

### Circuit Description

The electronic brake control module (EBCM) monitors the voltage level available for system operation. If the voltage level is too high, damage may result in the system. When the EBCM detects a high voltage condition, the EBCM turns OFF the system relay which removes battery voltage from the solenoid valves and pump motor.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0900 Device Voltage High

### Conditions for Running the DTC

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

### Conditions for Setting the DTC

The system voltage is greater than 17 volts for 0.72 second.

### Action Taken When the DTC Sets

If equipped, the following actions occur:

• | The EBCM disables the antilock brake system (ABS)/traction control system (TCS)/vehicle stability enhancement system (VSES) for the duration of the ignition cycle.

• | The DRP does not function optimally.

• | The ABS indicator turns ON.

• | The Traction Control and Active Handling indicator turns ON.

• | The driver information center (DIC) displays the following messages:

- | Service ABS

- | Service Traction System

- | Service Active Handling

### 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

A possible cause of this DTC is overcharging.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Use the scan tool in order to inspect the voltage to the EBCM.

2. Use the scan tool in order to inspect the voltage to the body control module (BCM). A high voltage value in multiple modules indicates a concern in the charging system.

3. Verifies that the condition is still present.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn OFF all of the accessories.
2. Install a scan tool.
3. Start the engine
4. Run the engine at approximately 2,000 RPM.
5. With a scan tool, observe the Switched System Battery Voltage parameter in the ABS data list.

Does the scan tool indicate that the voltage is greater than the specified value?

16.3V

Go to Step 3

Go to Diagnostic Aids

3 | With a scan tool, observe the Battery Volts parameter in body control module (BCM) data list. Does the scan tool indicate the voltage is greater than the specified value? | 16.3V | Go to Diagnostic System Check - Vehicle | Go to Step 4
4 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the conditions for Running the DTC as specified in the supporting test.

Does the DTC reset?

--

Go to Step 5

Go to Diagnostic Aids

5 | Replace the electronic brake control module (EBCM). Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 6 | --
6 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting test.

Does the DTC reset?

--

Go to Step 2

System OK