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 Ref. to WIRING SYSTEM>BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. 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)]. Ref. 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. Turn the ignition switch to OFF.
   2. Disconnect the radar sensor connectors LH and RH.
   3. Using a tester, measure the resistance between radar sensor RH connector (harness side) and radar sensor LH connector (harness side).

      Connector and 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 and 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 and 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.

   Terminals 

   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. Ref. 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)]. Ref. 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. Ref. 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. Ref. to BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>RADAR SENSOR .

   NOTE: When one of radars become faulty, the DTC B2350 is recorded in the radar on the other side as communication error. Therefore, the radar sensor that display the DTC is normal. And to rectify the problem, the radar sensor on the opposite side of the sensor that displayed the DTC must be replaced.

   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.