Dump and Isolation Valve Testing

Antilock Brake System

Diagnostic Information and Procedures

Dump and Isolation Valve Testing

Pressure Dump Test Procedure

1. Apply the parking brake fully.
2. Start the engine and allow the engine to idle.
3. Select the desired Dump Valve Solenoid Test on the scan tool.
4. Apply the brake and maintain steady pressure on the brake pedal.
5. Command the solenoid On and verify that the brake pedal drops to the floor.

Wheel Isolation Test Procedure

1. Apply the parking brake fully.
2. Start the engine and allow the engine to idle.
3. Select the desired Isolation Valve Solenoid Test on the scan tool.
4. Apply the brake with very light pressure, only enough to open the brake switch.
5. Command the solenoid On and then immediately apply firm and steady pressure to the brake pedal.
6. The EBCM automatically de-energizes the solenoid after about 5 seconds. When this occurs, verify that the brake pedal drops about 2.2 cm (1 inch).