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: 

• ABS does not operate.
• VDC does not operate.
• Hill start assist does not operate. (Models without EyeSight)
• AVH does not function. (Models with EyeSight)
• EyeSight does not operate. (Models with EyeSight)

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:  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 VDC Control Module & H/U. 

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

   Is the bracket deformation-free?

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

   Yes:  Go to  3.

   No:  Repair the defective part.

   • Install VDC Control Module & H/U properly.
   • Replace the bracket if faulty.
   • Tighten the VDC Control Module & H/U installation bolt. Refer to VEHICLE DYNAMICS CONTROL (VDC)>GENERAL DESCRIPTION>COMPONENT>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDC Control Module & 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, select "Data monitor". Refer to VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)>SUBARU SELECT MONITOR>OPERATION>READ CURRENT DATA .
   4. Read the «Yaw Rate Sensor» displayed on display.

   Is the reading of «Yaw Rate Sensor»-4 deg/s - 4 deg/s?

   Yes:  Go to  4.

   No:  Replace the VDC Control Module & H/U. Refer to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDC Control Module & 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, select "Data monitor". Refer to VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)>SUBARU SELECT MONITOR>OPERATION>READ CURRENT DATA .
   4. Read the «Steering Angle Sensor» displayed on display.

   Is the reading of «Steering Angle Sensor»-10 - 10°?

   Yes:  Go to  5.

   No:  Perform the centering adjustment of steering wheel.

5. CHECK VDC Control Module & H/U. 
   1. Turn the ignition switch to OFF.
   2. Perform the Clear Memory Mode. Refer to VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)>CLEAR MEMORY MODE .
   3. Perform the Inspection Mode. Refer to VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)>INSPECTION MODE .
   4. Read the DTC. Refer to VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is the same DTC displayed?

   Yes:  Replace the VDC Control Module & H/U. Refer to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDC Control Module & H/U) .

   No:  Go to  6.

6. CHECK DETECTION OF OTHER DTCS FOR VDC. 

   Refer to VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is any other DTC displayed?

   Yes:  Perform the diagnosis according to DTC. Refer to VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)>LIST OF DIAGNOSTIC TROUBLE CODE (DTC) .

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