Valve Solenoid-Pressure Release

The Pressure Release Mode activates the selected hydraulic wheel circuit valves, placing them in the pressure reduce position. When in the pressure reduce position, the valve will allow wheel caliper pressure to be returned to the master cylinder circuit. This is done under actual operating conditions because the Electronic Brake/Traction Control Module (EBTCM) has determined that the wheel is moving too slowly, and holding additional master cylinder pressure from it has not allowed it to rotate at an appropriate speed. The scan tool commands the valves to these positions which should allow the technician to spin the wheel even though an assistant is applying pressure to the brake pedal. Perform the test as follows:
1. Ignition OFF.
2. Install the scan tool.
3. Turn ignition to RUN.
4. Raise vehicle such that wheels are about 6 inches off the floor with the transmission in neutral.
5. Have an assistant press and hold the brake pedal.
6. Select Valve Solenoid Test. Have the assistant command RELEASE PRESSURE with the scan tool.
7. Attempt to move the wheel being tested by hand; it should move even though the assistant is applying pressure to the brake pedal. The front wheels may be difficult to turn by hand, but can be moved if the system is working properly.