HYDRAULIC UNIT (HU) CHECK


caution
  • The roller of the braking force tester and the tyre should be dry during testing.
  • When testing the front brakes, apply the parking brake. When testing the rear brakes, stop the front wheels with chocks.
1.Jack up the vehicle. Then support the vehicle with rigid racks at the specified jack-up points or place the front or rear wheels on the rollers of the braking force tester.
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.
caution Before connecting or disconnecting M.U.T.-III, always turn the ignition switch to the "LOCK" (OFF) position.
Before setting M.U.T.-III, turn the ignition key to the "LOCK" (OFF) position.
4.After checking that the selector lever is in neutral, start the engine.
5.When carrying out the actuator tests No.01 to 04, perform the actuator tests using M.U.T.-III while depressing the brake pedal. When carrying out the actuator tests, rotate the wheel by hands to confirm that the braking force changes.
note
  • When ABS-ECU is disabled due to the fail-safe function, the M.U.T.-III actuator test cannot be performed.
  • After the actuator test has been performed, the ABS warning lamp and brake waning lamp illuminate until the ignition switch is turned to "ON" again or the communication between M.U.T.-III and ABS-ECU is terminated.
6.

This is indicated as shown in the above.
7.When any malfunction has been found, take a necessary action according to the "Judgement Table."
Display on M.U.T.-III
 Operation
 Test result
 Judgement
 Cause
 Measure
01 FL wheel ABS drive
02 FR wheel ABS drive
03 RL wheel ABS drive
04 RR wheel ABS drive
  • Depress the brake pedal to lock the wheel.
  • Select the vehicle to be inspected using M.U.T.-III, perform the actuator test.
  • Rotate the selected wheel by hands to confirm the braking force.

 Braking force decreases for 3 seconds from the lock status.
 Normal
 -
 -
The wheel does not lock even if the brake pedal is depressed.
 Error
 Clogged brake line other than hydraulic unit
 Check and clean the brake line.
Clogged hydraulic circuit in the hydraulic unit
 Replace the hydraulic unit assembly.
Braking force does not decrease.
 Faulty routing of hydraulic unit brake tube
 Route the brake tube correctly.
Malfunction of hydraulic unit solenoid valve operation
 Replace the hydraulic unit assembly.
8.After the inspection, turn the ignition switch to the LOCK (OFF) position, and then disconnect M.U.T.-III.

Hydraulic unit installation adjustment
Refer to .