Brake Pressure Application Testing (W/JL4)
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.
Important: Before performing the following tests, perform all of the isolation valve tests described in the wheel isolation test procedure. A malfunctioning isolation valve may cause pressure to be applied to multiple wheels, instead of to just one wheel as commanded.
If the brake being tested fails to apply, does not hold for the full 9 second period or releases slowly after the 9 second hold, the TC Isolation Valve Test has failed.