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  .

   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. 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.

   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 .

      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.