Hydraulic Unit (HU) Check

HYDRAULIC UNIT (HU) CHECK

CAUTION: Turn the ignition switch off before connecting or disconnecting the scan tool.

1. Jack up the vehicle and support the vehicle with jack stands placed at the specified jack-up points or place the wheels which are checked on the rollers of the braking force tester.

CAUTION:
1. The roller of the braking force tester and the tire should be dry during testing.
2. When testing the front brakes, apply the parking brake. When testing the rear brakes, stop the front wheels by using a wheel chock.

2. Release the parking brake, and feel the drag force (drag torque) on each road wheel.
When using the braking force tester, take a reading of the brake drag force.
3. Turn the ignition key to the OFF position and set the scan tool.
4. After checking that the shift lever or the selector lever is in neutral, start the engine.
5. Use the scan tool to force-drive the actuator.

NOTE:
1. During the actuator test, the ABS warning light will illuminate and the anti-lock control will be canceled.
2. When the ABS has been interrupted by the fail-safe function, the scan tool actuator testing cannot be used.

6. Turn the wheel by hand and check the change in braking force when the brake pedal is depressed.
When using the braking force tester, depress the brake pedal until the braking force is at the following values, and check that the braking force decreases when the actuator is force-driven.

The result should be as shown in the following diagram.
7. If the result of inspection is abnormal, correct according to the Diagnostic Table below.

Diagnostic Table

8. After inspection, disconnect the scan tool immediately after turning the ignition switch to OFF.