DTC C1721: Yaw Rate Sensor

DTC detecting condition: 

• A fault is detected if the sensor signal value is not correct.
• A fault is detected if the steering angle sensor signal/lateral G sensor signal change while the yaw rate sensor signal indicates a constant value.
• A fault is detected if the communication status of yaw rate sensor is abnormal.

Trouble symptom: 

• VSC (VDC) does not operate.
• EyeSight does not operate.

1. INTERVIEW CUSTOMERS  .

   Check if the vehicle ran the road with banks or sandy surface (which does not mean a dirt road).

   Did the vehicle run the road with banks or sandy surface (which does not mean a dirt road)?

   Yes:  VSC (VDC) Control Module & H/U may record DTC when the vehicle ran the road with banks or sandy surface (which does not mean a dirt road).

   No:  Go to  2.

2. CHECK INSTALLATION OF VSC (VDC) CONTROL MODULE & H/U  .

   Is VSC (VDC) Control Module & H/U installed properly without being tilted?

   Is the bracket deformation-free?

   Are the VSC (VDC) Control Module & H/U installation bolts installed without missing or getting loose?

   Yes:  Go to  3.

   No:  Repair the defective part.

   • Install VSC (VDC) Control Module & H/U properly.
   • Replace the bracket if faulty.
   • Tighten the VSC (VDC) Control Module & H/U installation bolt. Ref. to VEHICLE STABILITY CONTROL>GENERAL DESCRIPTION>COMPONENT>VSC (VDC) CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VSCCM & H/U) .

     Go to  3.

3. CHECK OUTPUT OF YAW RATE & G SENSOR WITH 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 [Yaw Rate Sensor] in the [Data Monitor] of [Brake Control]. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR .

   Is the value of [Yaw Rate Sensor] between -4 - 4 deg/s?

   Yes:  Go to  4.

   No:  Replace the VSC (VDC) Control Module & H/U. Ref. to VEHICLE STABILITY CONTROL>VSC (VDC) CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VSCCM & H/U) .

4. CHECK OUTPUT OF STEERING ANGLE SENSOR WITH 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 [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  5.

   No:  Perform the centering adjustment of steering wheel.

5. CHECK VSC (VDC) CONTROL MODULE & H/U  .
   1. Turn the ignition switch to OFF.
   2. Using the Subaru Select Monitor, perform the clear memory of [Brake Control]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   3. Execute the inspection mode. Ref. to BRAKE CONTROL (DIAGNOSTICS)>INSPECTION MODE .
   4. Read the DTC of [Brake Control] using the Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is the same DTC displayed?

   Yes:  Replace the VSC (VDC) Control Module & H/U. Ref. to VEHICLE STABILITY CONTROL>VSC (VDC) CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VSCCM & H/U) .

   No:  Go to  6.

6. CHECK DETECTION OF OTHER DTCS FOR VSC (VDC)  .

   Read the DTC of [Brake Control] using the Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is any other DTC displayed?

   Yes:  Perform the diagnosis according to the DTC. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Currently, it is normal. There may have been a temporary poor contact in the harness and connector or a temporary noise interference.