For 1990-2009 cars

### Automated Test

The Automated Test cycles each valve solenoid, the pump motor, and the necessary relays in order to check component operation. If a malfunction is detected, the EBCM/EBTCM will set DTCs which will be displayed upon completion of the test. Complete the following steps in order to perform the test:

1. Turn the ignition switch to the OFF position.
2. Install the scan tool.
3. Turn the ignition switch to the RUN position.
4. Select Special Functions.
5. Select AUTOMATED Test.
6. Run the AUTOMATED Test.
7. Note any DTCs set.

### Valve Solenoid -- Pressure Hold Test

The Pressure Hold Mode activates the selected wheel circuit Inlet valve, placing the valve in the pressure hold position. When the valve is in the pressure hold position, the valve will not allow the master cylinder to deliver pressure to the hydraulic wheel circuit. This is done under actual operating conditions because the EBCM/EBTCM determines that the wheel is moving too slowly. The master cylinder pressure is held from the wheel in order to allow the wheel to rotate at an appropriate speed. The Scan Tool commands the valve to close. This should allow the technician to spin the wheel, even though an assistant is applying the brake pedal. Complete the following steps in order to perform the test:

1. Turn the ignition switch to the OFF position.
2. Install the scan tool.
3. Turn the ignition switch to the RUN position.
4. Place the transmission in (N) Neutral.
5. Raise the vehicle until the wheels are six inches from the floor.
6. Select the Valve Solenoid Test.
7. Have an assistant command Hold Pressure with the scan tool.
8. Have the assistant press and hold the brake pedal.
9. Attempt to move the test wheel by hand.

• | The wheel should move even though the assistant is applying the brake pedal.

• | The front wheels may be difficult to move by hand, but can be turned if the system is working properly.

### Valve Solenoid -- Pressure Release Test

The Pressure Release Mode activates the selected wheel circuit Outlet valve, placing the valve in the pressure release position. When the Outlet valve is in the pressure release position, the valve allows the wheel caliper pressure to be returned to the master cylinder. This is done under actual operating conditions because the EBCM/EBTCM determines that the wheel is moving too slowly. The master cylinder pressure is held from the wheel by closing the Inlet valve and pressure is released by opening the Outlet valve. This allows the wheel to rotate at an appropriate speed. The scan tool commands the Inlet valve to close and the Outlet valve to open. This should allow the technician to spin the wheel, even though an assistant is applying the brake pedal. Complete the following steps in order to perform the test:

1. Turn the ignition switch to the OFF position.
2. Install the scan tool.
3. Turn the ignition switch to the RUN position.
4. Place the transmission in (N) Neutral.
5. Raise the vehicle until the wheels are six inches from the floor.
6. Have the assistant press and hold the brake pedal.
7. Select the Valve Solenoid Test.
8. Have an assistant command Release Pressure with the scan tool.
9. Attempt to move the test wheel by hand.

• | The wheel should move even though the assistant is applying the brake pedal.

• | The front wheels may be difficult to move by hand, but can be turned if the system is working properly.

### Traction Control System Test

This test runs the pump motor in order to apply fluid pressure to the front wheel circuits (TCS equipped vehicles only). Complete the following steps in order to perform the test:

1. Turn the ignition switch to the OFF position.
2. Install the scan tool.
3. Turn the ignition switch to the RUN position.
4. Place the transmission in (N) Neutral.
5. Raise the vehicle until the wheels are six inches from the floor.
6. Select Special Functions.
7. Select TCS Test.
8. Command the TCS Test on using the scan tool. The pump motor will turn on for about 25 seconds.
9. Attempt to move a front wheel by hand. The wheel should not move due to the pump motor running and applying pressure to the front wheels.