Hydraulic Functional Control

HYDRAULIC FUNCTIONAL CONTROL
Tools Required
Scan Tool
This test is used to verify base brake apply and ABS release, hold and apply functions. During testing, the scan tool will provide information on any problem that may be encountered.
1. Turn the ignition switch to LOCK.
2. Raise and suitably support the vehicle so that all four wheels are off the ground.
3. Install the brake cartridge into the scan tool and connect it to the data link connector (DLC). Power the scan tool using the battery adapter.
4. Turn the ignition switch to ON.
5. Select a channel to test - left front, right front, or rear. When testing the rear brakes, both rear wheels should rotate and not rotate together at the various points in the test. This is true because both rear brake pressures are controlled together.
6. Firmly press the brake pedal. The pedal should remain high and firm.
7. Have an assistant attempt to rotate the wheel being tested. If the wheel does not rotate, base brake apply is functioning properly.
8. With the brake pedal still pressed, press the (up arrow) key on the scan tool to begin the test. The brake pedal should remain high and firm. If the brake pedal drops toward the floor, verify the solenoid electrical connectors are connected to the correct solenoids.
9. With the brake pedal still pressed, have the assistant attempt to rotate the wheel. The wheel should rotate with little or no resistance for the full 18 seconds of this test.
10. After 18 seconds, brake pressure will be applied, and a slight bump may be felt in the brake pedal. This is normal. The assistant should not be able to rotate the wheel at this point.