DTC B2C0C: RLC Sonar Sensor Circuit/No Signal

Outline of diagnosis: 

Sonar sensor (left inner) harness is open.

Time needed for diagnosis: 

1200 ms

Recovery conditions: 

Ignition switch OFF → ON

Wiring diagram: 

Reverse Automatic Braking system Ref. to WIRING SYSTEM>REVERSE AUTOMATIC BRAKING

Courtesy of SUBARU OF AMERICA, INC.

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

   Is DTC B2C0C displayed? (Current code)

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

      Connector & terminal 

      (L81) No. 11 - (L114) No. 2:

      (L81) No. 21 - (L114) No. 1:

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

   Is DTC B2C0C displayed? (Current code)

   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 inner). Ref. to REVERSE AUTOMATIC BRAKING>SENSOR AND HARNESS