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HOMESERVICE MANUALSSUBARU2016LEGACY 2.5IREPAIR AND DIAGNOSISBRAKESTRACTION CONTROLVEHICLE DYNAMICS CONTROL (VDC) SYSTEM (DIAGNOSTICS)DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)DTC C1811 SYSTEMTROUBLE SYMPTOM
2016 Subaru Legacy 2.5i

DTC C1811 System: Trouble Symptom

2016 Subaru Legacy 2.5iSECTION Trouble Symptom
  • ABS does not operate.
  • VDC does not operate.
  • Hill hold does not function.
  • EyeSight does not operate. (Models with EyeSight)
DIAGNOSTIC PROCEDURE

Step Check Yes No
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?		 Go to step 2  . 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°? Go to step 3  . Perform the centering adjustment of steering wheel, and perform the VDC sensor midpoint setting mode. < Ref. to VDC SENSOR MIDPOINT SETTING MODE , ADJUSTMENT, VDC Control Module and Hydraulic Control Unit (VDCCM & H/U). > Go to step 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, select "Data monitor". < Ref. to READ CURRENT DATA , OPERATION, Subaru Select Monitor. >
  3. Read the «Steering Angle Sensor» displayed on display.
 Is the indicated reading of the steering angle sensor -10° - 10°? Go to step 4  . Check the installation of the steering wheel and steering angle sensor, and replace the parts unless wrong installations are found.
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, select "Data monitor". < Ref. to READ CURRENT DATA , OPERATION, Subaru Select Monitor. >
  4. Read output of sensors displayed on display.
 Are the indicated reading of sensor outputs following values?
Lateral G sensor: -2 - 2 m/s2
Longitudinal G sensor: -2 - 2 m/s2
Yaw rate sensor: -4 - 4 deg/s		 Go to step 5  . Recheck from step 1, and if the problem is not solved, go to next. Go to step 8  .
5 SET 0 POINT SETTING OF LONGITUDINAL G SENSOR USING SUBARU SELECT MONITOR. 
  1. Using the Subaru Select Monitor, select "Work Support".
  2. Perform the VDC sensor midpoint setting mode. < Ref. to VDC SENSOR MIDPOINT SETTING MODE , ADJUSTMENT, VDC Control Module and Hydraulic Control Unit (VDCCM & H/U). >
 Is 0 point setting successful? Go to step 6  . Recheck from step 1, and when the 0 point setting is not possible, replace the VDCCM & H/U and steering angle sensor. < Ref. to VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) . > < Ref. to STEERING ANGLE SENSOR . >
6 PERFORM DRIVING TEST. 
< Ref. to INSPECTION MODE . >		 Does the ABS warning light or VDC warning light illuminate during driving?
Does ABS or VDC operate abnormally?		 Recheck from step 1, and when the warning lights illuminate or improperly operate, replace the VDCCM & H/U. < Ref. to VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) . > Go to step 7  .
7 CHECK OUTPUT OF SENSORS USING SUBARU SELECT MONITOR. 
  1. Park the vehicle on a level surface.
  2. Using the Subaru Select Monitor, select "Data monitor". < Ref. to READ CURRENT DATA , OPERATION, Subaru Select Monitor. >
  3. Read output of sensors displayed on display.
 Are the indicated reading of sensor outputs following values?
Lateral G sensor: -2 - 2 m/s2
Longitudinal G sensor: -2 - 2 m/s2
Yaw rate sensor: -4 - 4 deg/s		 Currently, it is normal. There may have been a poor contact in the harness and connector or a temporarily noise interference. Replace the VDCCM & H/U. < Ref. to 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, select "Data monitor". < Ref. to READ CURRENT DATA , OPERATION, Subaru Select Monitor. >
  4. Read output of sensors displayed on display.
 When VDCCM & H/U is in a horizontal position, are the indicated reading of sensor outputs following values?
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		 Check the bracket and brake pipe, and install VDCCM & H/U in a horizontal position to the vehicle. Replace the VDCCM & H/U. < Ref. to VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) . >
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.