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DTC C1811: System

DTC detecting condition: 

A fault is detected if VDC control status continues for 15 seconds or more.

Trouble symptom: 

  1. CHECK INSTALLATION OF VDCCM&H/U  .

    Is VDCCM&H/U installed properly without being tilted?

    Is the bracket deformation-free?

    Are the VDCCM&H/U installation bolts installed without missing or getting loose?

    Yes:  Go to  2.

    No:  Repair the defective part.

    Go to  2.

  2. CHECK STEERING WHEEL  .
    1. Drive the vehicle on a flat road.
    2. Park the vehicle straight.
    3. Check the steering wheel for deviation from center.

    Is the deviation from the center of steering wheel less than 5°?

    Yes:  Go to  3.

    No:  Adjust the centering of steering wheel, and perform the VDC sensor midpoint setting mode. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC Control Module and Hydraulic Control Unit (VDCCM&H/U)>ADJUSTMENT>VDC SENSOR MIDPOINT SETTING MODE .

    Go to  3.

  3. CHECK OUTPUT OF STEERING ANGLE SENSOR USING SUBARU SELECT MONITOR  .
    1. Adjust steering wheel to the center position.
    2. Select the [Data Monitor] using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .
    3. Read [Steering Angle Sensor] indicated on the display screen.

    Is the value of [Steering Angle Sensor] between -10° - 10 deg?

    Yes:  Go to  4.

    No:  Check the installation of the steering wheel and steering angle sensor, and correct the installation if it is improper. If the installation condition is correct, replace the sensor.

  4. CHECK OUTPUT OF SENSORS USING SUBARU SELECT MONITOR  .
    1. Drive the vehicle on a flat road.
    2. Park the vehicle straight.
    3. Select the [Data Monitor] using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .
    4. Read [Lateral G Sensor], [Longitudinal G Sensor], and [Yaw Rate Sensor] indicated on the display screen.

    Is the reading of each sensor following value?

    [Lateral G Sensor]: -2 - 2 m/s^2

    [Longitudinal G Sensor]: -2 - 2 m/s^2

    [Yaw Rate Sensor]: -4 - 4 deg/s

    Yes:  Go to  5.

    No:  Recheck from step 1, and if the problem is not solved, Go to  8.

  5. SET 0 POINT SETTING OF LONGITUDINAL G SENSOR USING SUBARU SELECT MONITOR  .
    1. Select the [Work Support] using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>WORK SUPPORT .
    2. Perform the VDC sensor midpoint setting mode. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC Control Module and Hydraulic Control Unit (VDCCM&H/U)>ADJUSTMENT>VDC SENSOR MIDPOINT SETTING MODE .

    Is 0 point setting successful?

    Yes:  Go to  6.

    No:  Recheck from step 1, and when the 0 point setting is not possible, replace the VDCCM&H/U and steering angle sensor. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM&H/U) . Ref. to VEHICLE DYNAMICS CONTROL (VDC)>STEERING ANGLE SENSOR .

  6. PERFORM DRIVING TEST  .

    Ref. to BRAKE CONTROL (DIAGNOSTICS)>INSPECTION MODE .

    Does the ABS warning light or VDC warning light illuminate during driving?

    Does ABS or VDC operate abnormally?

    Yes:  Recheck from step 1, and when the warning lights illuminate or improperly operate, replace the VDCCM&H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM&H/U) .

    No:  Go to  7.

  7. CHECK OUTPUT OF SENSORS USING SUBARU SELECT MONITOR  .
    1. Park the vehicle on a level surface.
    2. Select the [Data Monitor] using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .
    3. Read [Lateral G Sensor], [Longitudinal G Sensor], and [Yaw Rate Sensor] indicated on the display screen.

    Is the reading of each sensor following value?

    [Lateral G Sensor]: -2 - 2 m/s^2

    [Longitudinal G Sensor]: -2 - 2 m/s^2

    [Yaw Rate Sensor]: -4 - 4 deg/s

    Yes:  Currently, it is normal. There may have been a temporary poor contact in the harness and connector or a temporary noise interference.

    No:  Replace the VDCCM&H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM&H/U) .

  8. CHECK OUTPUT OF SENSORS USING SUBARU SELECT MONITOR  .
    1. Remove the VDCCM&H/U installation bolt and bracket.
    2. Keep VDCCM&H/U in a horizontal position.
    3. Select the [Data Monitor] using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .
    4. Read [Lateral G Sensor], [Longitudinal G Sensor], and [Yaw Rate Sensor] indicated on the display screen.

    When VDCCM&H/U is in a horizontal position, is the reading of each sensor following value?

    [Lateral G Sensor]: -1.5 - 1.5 m/s^2

    [Longitudinal G Sensor]: -1.5 - 1.5 m/s^2

    [Yaw Rate Sensor]: -4 - 4 deg/s

    Yes:  Check the bracket and brake pipe, and install VDCCM&H/U in a horizontal position to the vehicle.

    No:  Replace the VDCCM&H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM&H/U) .

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