Hydraulic Unit Check: Notes

Required Special Tools: 

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: V.C.I.
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A

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.
   CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOOK" (OFF) position before connecting or disconnecting scan tool MB991958.
3. Turn the ignition switch to the "LOCK" (OFF) position and set scan tool MB991958 as shown in the illustration.
4. After checking that the selector lever is in neutral, start the engine.
5. Use scan tool MB991958 to force-drive the actuator.
   NOTE: The ABS system will switch to the scan tool mode and the ABS warning light will illuminate.
   NOTE: When the ABS has been interrupted by the fail-safe function, scan tool MB991958 actuator testing cannot be used.
   Fig 1: Connecting Scan To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   Fig 2: Actuator Test - Blinking Pattern

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
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 changes to the brake drag force inspected in step  2 when the actuator is force-driven. The result should be as shown in the diagram above.
   BRAKE DRAG FORCE SPECIFICATIONS
   
   

   Front wheel	785 -981 N (176 -220 lb)
   Rear wheel	588 -784 N (132 -176 lb)

7. If the result of inspection is abnormal, repair according to the Diagnosis Chart.
   DIAGNOSIS CHART
   
   

   DIAGNOSIS TABLE
   MUT-III DISPLAY	OPERATION	INSPECTION RESULT	JUDG MENT	PROBABLE CAUSE	REMEDY
   01 FR VALBE 02 FL VALBE 03 RR VALBE 04 RL VALBE	Depress brake pedal to lock wheel. Using scan tool MB991958, select the wheel to be checked and force the actuator to operate. Turn the selected wheel manually to check the change of brake force.	Brakeforce is released for three seconds after wheels have been locked.	Normal	-	-
   		Wheel does not lock when brake pedal is depressed.	Abnor mal	Clogged brake line other than hydraulic unit	Check and clean brake line
   				Clogged hydraulic circuit in hydraulic unit	Replace hydraulic unit assembly
   		Brake force is not released		Incorrect hydraulic unit brake tube connection	Connect correctly
   				Hydraulic unit solenoid valve not functioning correctly	Replace hydraulic unit assembly

8. After inspection, disconnect the scan tool immediately after turning the ignition switch to the "LOCK" (OFF) position.