Vehicle Dynamics Control (Vdc): Overview Subaru Forester SH

CHECKING THE HYDRAULIC UNIT VDC OPERATION USING A PRESSURE GAUGE

1. Lift up the vehicle, and remove the wheels.
2. Remove the air bleeder screws from FL and FR caliper bodies.
3. Connect two pressure gauges to FL and FR caliper bodies. CAUTION: Use a pressure gauge used exclusively for brake fluid measurement. Do not use the pressure gauge used for the measurement of transmission oil pressure. Doing so will cause the piston seal to expand and deform. NOTE: Wrap sealing tape around the pressure gauge.
4. Bleed air from the pressure gauge.
5. Perform VDC sequence control. Refer to «VDC SEQUENCE CONTROL»(ref-325347-S34482360592009071800000) .
6. When the hydraulic unit begins work, first the FL side performs compression, hold, and decompression, and then the FR side performs compression, hold, and decompression.
7. Read values indicated on the pressure gauge and check if the fluctuation of the values between decompression and compression meets specification. Also, step on the brake pedal and check for any abnormal hardness or softness of the brake. WHEEL SPECIFICATION CHART Front wheel Rear wheel When pressurized 3,000 kPa (31 kgf/cm 2 , 441 psi) or more 3,000 kPa (31 kgf/cm 2 , 441 psi) or more When depressurized 500 kPa (5 kgf/cm 2 , 73 psi) or less 500 kPa (5 kgf/cm 2 , 73 psi) or less
8. Disconnect the pressure gauges from FL and FR caliper bodies.
9. Install the air bleeder screws of FL and FR caliper bodies.
10. Remove the air bleeder screws from RL and RR caliper bodies.
11. Connect two pressure gauges to RL and RR caliper bodies.
12. Bleed air from RL and RR caliper bodies, and pressure gauge.
13. Perform VDC sequence control. Refer to «VDC SEQUENCE CONTROL»(ref-325347-S34482360592009071800000) .
14. When the hydraulic unit begins work, first the RR side performs compression, hold, and decompression, and then the RL side performs compression, hold, and decompression.
15. Read the values indicated on the pressure gauges and check if it is within specification. Also, step on the brake pedal and check for any abnormal hardness or softness of the brake.
16. Disconnect the pressure gauge from the RL and RR caliper bodies.
17. Install the air bleeder screws of RL and RR caliper bodies.
18. Bleed air from the brake line.

Scheme 56

1. Set wheels other than the one to measure free rollers.
2. Prepare to operate the VDC sequence control. Refer to «VDC SEQUENCE CONTROL»(ref-325347-S34482360592009071800000) .
3. Set the front wheels or rear wheels on the brake tester and set the gear to neutral.
4. Operate the brake tester.
5. Perform VDC sequence control. Refer to «VDC SEQUENCE CONTROL»(ref-325347-S34482360592009071800000) .
6. When the hydraulic unit begins to work, check the following work sequence. The FL wheel performs compression, hold and decompression in sequence, and subsequently the FR wheel repeats the cycle. The RR wheel performs compression, hold and decompression in sequence, and subsequently the RL wheel repeats the cycle.
7. Read values indicated on the brake tester and check if the fluctuation of the values between decompression and compression meets specification. WHEEL SPECIFICATION CHART Front wheel Rear wheel When pressurized 2,000 N (204 kgf, 450 lbf) or more 2,000 N (204 kgf, 450 lbf) or more When depressurized 500 N (51 kgf, 112 lbf) or less 500 N (51 kgf, 112 lbf) or less
8. After the inspection, depress the brake pedal and check that it is not abnormally hard, and tightness is normal.

OPERATION

1. While the ABS sequence control is being performed, the operation of the hydraulic unit can be checked using the brake tester or pressure gauge after the hydraulic unit solenoid valve operation.
2. ABS sequence control can be started by the Subaru Select Monitor.

1. While VDC sequence control is being performed, the operation of the hydraulic unit can be checked using the brake tester or pressure gauge after the hydraulic unit solenoid valve operation.
2. VDC sequence control can be started by the Subaru Select Monitor.