DTC C1252: Wheel Speed Sensor Signal Of One Of The Wheels

DTC Detecting condition: 

• Defective ABS wheel speed sensor signal (noise, irregular signal, etc.)
• Defective magnetic encoder
• When a wheel is turned freely for a long time

Trouble symptom: 

• ABS does not operate.
• VDC does not operate.
• EBD may not operate.
• AVH does not function.
• EyeSight does not operate. (Model with EyeSight)

1. WHETHER A WHEEL TURNED FREELY OR NOT. 

   Check if the wheels have been turned freely for one minute or more, such as when the vehicle is jacked-up, under full-lock cornering or when the wheels are not in contact with road surface.

   Did the wheels turn freely?

   Yes:  VDC System is normal. Using the Subaru Select Monitor, perform the clear memory. Ref. to COMMON (DIAG)>CLEAR MEMORY .

   NOTE: This diagnostic trouble code may sometimes occur if the wheels turn freely for a long time, for example when the vehicle is towed or jacked up, or when steering wheel is continuously turned all the way.

   No:  Go to  2.

2. CHECK TIRE SPECIFICATIONS. 

   Turn the ignition switch to OFF.

   Are the tire specifications correct?

   Yes:  Go to  3.

   No:  Replace the tire.

3. CHECK WEAR OF TIRE. 

   Is the tire worn excessively?

   Yes:  Replace the tire.

   No:  Go to  4.

4. CHECK TIRE INFLATION PRESSURE. 

   Is the tire pressure correct?

   Yes:  Go to  5.

   No:  Adjust the tire pressure.

5. CHECK INSTALLATION OF ABS WHEEL SPEED SENSOR. 

   Are the ABS wheel speed sensor installation bolts tightened to 7.5 N.m (0.76 kgf-m, 5.5 ft-lb)? (Four wheels)

   Yes:  Go to  6.

   No:  Tighten the ABS wheel speed sensor installation bolts.

6. CHECK ABS WHEEL SPEED SENSOR SIGNAL. 

   Check the ABS wheel speed sensor. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>FRONT ABS WHEEL SPEED SENSOR>INSPECTION . Ref. to VEHICLE DYNAMICS CONTROL (VDC)>REAR ABS WHEEL SPEED SENSOR>INSPECTION .

   Is the check result OK?

   Yes:  Go to  8.

   No:  Go to  7.

7. CHECK ABS WHEEL SPEED SENSOR OR MAGNETIC ENCODER. 

   Are there foreign matters adhered to the tip of ABS wheel speed sensor or magnetic encoder? Or is there any breakage or damage? (Four wheels)

   Yes:  Remove dirt thoroughly. Also replace the ABS wheel speed sensor or magnetic encoder as a unit with hub unit bearing if it is broken or damaged.

   No:  Go to  8.

8. CHECK VDC Control Module & H/U. 
   1. Connect all connectors.
   2. Using the Subaru Select Monitor, perform the clear memory. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   3. Execute the inspection mode. Ref. to BRAKE CONTROL (DIAGNOSTICS)>INSPECTION MODE .
   4. Read the DTC using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is the same DTC displayed?

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

   No:  Go to  9.

9. CHECK DETECTION OF OTHER DTCS FOR VDC. 

   Read the DTC using 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.