DTC B2350: Rear Radar Communication Error Between Master And Slave

DTC detecting condition: 

• Defective harness for CAN communication between radar sensor LH - radar sensor RH.
• Defective radar sensor

Trouble symptom: 

• All functions of BSD/RCTA stop.
• Fail icon is displayed in the combination meter LCD display.
• Failure-related notification is displayed for approx. two seconds on LCD display in the combination meter.

Wiring diagram: 

BSD/RCTA system Refer to WIRING SYSTEM (IMPREZA MODEL)>BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>WIRING DIAGRAM . Refer to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>WIRING DIAGRAM . Refer to WIRING SYSTEM (CROSSTREK MODEL (HEV))>BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC. 

   Using the Subaru Select Monitor, read the DTCs of [Blind Spot Detection/Rear Cross Traffic Alert (RH)] or [Blind Spot Detection/Rear Cross Traffic Alert (LH)]. Refer to BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   • Blind Spot Detection/Rear Cross Traffic Alert (RH)
   • Blind Spot Detection/Rear Cross Traffic Alert (LH)

   Is DTC B2350 displayed? (Current malfunction)

   Yes:  Go to  2.

   No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK HARNESS (OPEN CIRCUIT). 
   1. Disconnect the radar sensor connectors LH and RH.
   2. Using a tester, measure the resistance between radar sensor RH connector (harness side) and radar sensor LH connector (harness side).

      Connector & terminal 

      (R25) No. 1 - (R61) No. 1:

      (R25) No. 6 - (R61) No. 6:

   Is the resistance less than 1 Ω?

   Yes:  Go to  3.

   No:  Repair the open circuit of harness between radar sensor RH connector and radar sensor LH connector.

3. CHECK HARNESS (SHORT BETWEEN LINES, GROUND SHORT CIRCUIT). 

   Using a tester, measure the resistance between radar sensor LH connectors (harness side) and the resistance between radar sensor LH connector (harness side) and chassis ground.

   Connector & terminal 

   (R25) No. 1 - (R25) No. 6:

   (R25) No. 1 - Chassis ground:

   (R25) No. 6 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes:  Go to  4.

   No:  Repair the short circuit of harness between radar sensor RH connector and radar sensor LH connector.

4. CHECK HARNESS (SHORT CIRCUIT TO POWER SUPPLY). 
   1. Turn the ignition switch to ON.
   2. Using a tester, measure the voltage between radar sensor LH connector (harness side) and chassis ground.

      Connector & terminal 

      (R25) No. 1 (+) - Chassis ground (-):

      (R25) No. 6 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes:  Go to  5.

   No:  Repair the short to power supply in harness between radar sensor RH connector and radar sensor LH connector.

5. CHECK RADAR SENSOR. (INTERNAL IMPEDANCE). 

   Using a tester, measure the internal impedance between radar sensor LH and radar sensor RH terminals.

   Terminal 

   Radar sensor LH

   No. 1 - No. 6:

   Radar sensor RH

   No. 1 - No. 6:

   Is the resistance approximately 120 Ω?

   Yes:  Go to  6.

   No:  Replace the radar sensor RH or radar sensor LH. Refer to BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>RADAR SENSOR .

6. CHECK BSD/RCTA. 
   1. Restore the vehicle to its original state.
   2. Using the Subaru Select Monitor, perform the clear memory of [Blind Spot Detection/Rear Cross Traffic Alert (RH)] or [Blind Spot Detection/Rear Cross Traffic Alert (LH)]. Refer to COMMON (DIAG)>CLEAR MEMORY .
      • Blind Spot Detection/Rear Cross Traffic Alert (RH)
      • Blind Spot Detection/Rear Cross Traffic Alert (LH)
   3. Perform the inspection mode. Refer to BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT (DIAGNOSTICS)>INSPECTION MODE .

   Is DTC B2350 displayed? (Current malfunction)

   Yes:  Replace the radar sensor on the opposite side of the sensor that displayed the DTC. Refer to BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>RADAR SENSOR .

   No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.