Wheel Isolation Test Procedure
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Apply the parking brake fully.
- Start the engine and allow the engine to idle.
- Select the desired Isolation Valve Solenoid Test on the scan tool.
- Apply the brake with very light pressure, only enough to open the brake switch.
- Command the solenoid On and then immediately apply firm and steady pressure to the brake pedal.
- 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).