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DTC C1811: System

DTC detecting condition: 

A fault is detected if VDC control status and ABS control status continue for a long period of time.

Trouble symptom: 

Failure detection pattern: 

Warning light/indicator light: 

The combination of DTC and warning light display may differ from the list depending on vehicle conditions and driving conditions at the time of failure detection.

  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.

  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:  Perform the centering adjustment 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. Using the Subaru Select Monitor, read data of [Steering Angle Sensor] in the [Data Monitor] of [Brake Control]. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .

    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. Using the Subaru Select Monitor, read data of [Lateral G Sensor], [Longitudinal G Sensor], and [Yaw Rate Sensor] in the [Data Monitor] of [Brake Control]. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .

    Is the reading of each sensor following value?

    [Lateral G Sensor]: -2 - 2 m/s2

    [Longitudinal G Sensor]: -2 - 2 m/s2

    [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  .

    Execute the inspection mode. 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. Using the Subaru Select Monitor, read data of [Lateral G Sensor], [Longitudinal G Sensor], and [Yaw Rate Sensor] in the [Data Monitor] of [Brake Control]. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .

    Is the reading of each sensor following value?

    [Lateral G Sensor]: -2 - 2 m/s2

    [Longitudinal G Sensor]: -2 - 2 m/s2

    [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. Using the Subaru Select Monitor, read data of [Lateral G Sensor], [Longitudinal G Sensor], and [Yaw Rate Sensor] in the [Data Monitor] of [Brake Control]. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .

    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/s2

    [Longitudinal G Sensor]: -1.5 - 1.5 m/s2

    [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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