Suspension Control ( Automatic - Electronic ): Service and Repair

Air bleeding discharges air trapped in oil in hydraulic lines during part replacement. Bleeding air from oil and oil lines is accomplished by directing pulsating oil under pressure so that all air in line is forced to accumulate at actuator's upper section. It is then discharged into atmosphere through air bleeder located on actuator. When front or rear pressure control unit is replaced, bleed air from its interior.
1. Lift vehicle until wheels are at least two inches above ground.
2. Start engine and allow to idle for approximately two minutes.
3. Connect CONSULT tool and set to WORK SUPPORT mode. Call up ``4. AIR BLEEDING.'' When NEXT is touched, followed by change over of bypass valve operations, display will show ``4. AIR BLEEDING.''
4. Check oil level in reservoir tank and add oil to it is slightly higher than specified level.

Fig. 49 Air Bleeding Control Pattern:

5. Touch START on CONSULT display. Display will then show control pattern shown in Fig. 49, and air bleed vibration will be executed.
6. After ensuring air bleed vibration is complete on display, stop engine.






Actuators

1. While bleeding air, check and add oil level in reservoir tank as needed.
2. Connect vinyl tube to air bleeder of actuator.
3. Slowly loosen air bleeder. Drain oil until air bubbles disappear. Torqueair bleeder to 4.3-5.8 ft. lbs.






4. If air is not completely bled from actuator, repeat air bleeding operation.











Pressure Control Units

When noise is persistently produced or after any pressure control unit is replaced, bleed air from pressure control unit using same procedures as actuators.
Each pressure control unit is equipped with two air bleeders. Bleed air from both bleeders.

Multivalve Unit

1. Race engine or drive vehicle until oil temperature rises to 140-158 °F or until Full Active Suspension oil cooler motor fan operates.
2. Connect CONSULT tool and perform ``4-wheel vibration'' mode of work support to allow oil to be circulated through system.
3. Sudden rise in oil pressure is required for testing. For this purpose, start engine with accelerator pedal depressed.
4. Increase engine speed to approximately 4000 rpm and maintain for 20 seconds. Stop engine and leave as is for three minutes.
5. Repeat steps 3 and 4 five to six times.
6. If noise is still heard after completing, leave vehicle for more than 30 minutes and re-perform above procedures.






OIL LEAK CHECK
Neutral pressure leak check
^ Start engine and idle it for approximately 2 minutes.
^ Set CONSULT to "WORK SUPPORT" mode and call up "5. PRESSURE LEAK CHECK 1" on CONSULT display.
When "NEXT" is touched, followed by air bleeding operations, display will show "5. PRESSURE LEAK CHECK 1"
^ Touch "START" to control actuator oil pressure at 4,609 kPa (47 kg/cm2, 668 psi).
While neutral pressure leak check is being executed, both flow control and fail-safe valves are held open.
^ After making sure neutral pressure control is completed on display, lift vehicle and hold it for at least 3 minutes.
^ Check that leaks are not present at pipes and connections. Lower vehicle so that wheels are approximately 50 mm (1.97 in) above ground.