DTC B2C0A: RL Sonar Sensor Circuit/No Signal

Outline of diagnosis: 

Sonar sensor (left corner) harness is open.

Time needed for diagnosis: 

1200 ms

Recovery conditions: 

Ignition switch OFF → ON

Wiring diagram: 

Reverse Automatic Braking Ref. to WIRING SYSTEM (IMPREZA MODEL)>REVERSE AUTOMATIC BRAKING>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>REVERSE AUTOMATIC BRAKING>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>REVERSE AUTOMATIC BRAKING>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the sonar sensor (left corner) connector.
   3. Connect the disconnected connectors.
   4. Turn the ignition switch to ON.
   5. Read the DTC of [Reverse Assist Braking] using the Subaru Select Monitor. Ref. to REVERSE AUTOMATIC BRAKING (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2C0A 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 BETWEEN SONAR SENSOR CONNECTOR AND RAB CONTROL MODULE CONNECTOR. (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the sonar sensor (left corner) connector and the RAB control module connector.
   3. Using a tester, measure resistance of the harness between the sonar sensor (left corner) connector and RAB control module connector.

      Connector and terminal 

      (R361) No. 8 - (R364) No. 1:

      (R361) No. 23 - (R364) No. 2:

   Is the resistance less than 10 Ω?

   Yes:  Go to  3.

   No:  Repair or replace the open circuit in the harness between sonar sensor connector and RAB control module connector.

3. CHECK SONAR SENSOR  .
   1. Switch the sonar sensor (left corner) and sonar sensor (left inner).
   2. Connect the disconnected connectors.
   3. Turn the ignition switch to ON.
   4. Read the DTC of [Reverse Assist Braking] using the Subaru Select Monitor. Ref. to REVERSE AUTOMATIC BRAKING (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2C0A displayed? (Current malfunction)

   Yes:  Replace the RAB control module. Ref. to REVERSE AUTOMATIC BRAKING>REVERSE AUTOMATIC BRAKING CONTROL MODULE .

   No:  Replace the sensor installed as a sonar sensor (left corner). Ref. to REVERSE AUTOMATIC BRAKING>SENSOR AND HARNESS .