DTC B2C12: RL Sonar Harness High

Outline of diagnosis: 

Sonar sensor (left corner) harness is shorted to power supply.

Time needed for diagnosis: 

1200 ms

Recovery conditions: 

Ignition switch OFF → ON

Wiring diagram: 

Reverse Automatic Braking Ref. to WIRING SYSTEM>REVERSE ASSIST BRAKING SYSTEM .

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 ASSIST BRAKING (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2C12 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. (SHORT CIRCUIT TO POWER SUPPLY)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the sonar sensor (left corner) connector and the RAB control module connector.
   3. Turn the ignition switch to ON.
   4. Using a tester, measure the voltage between sonar sensor (left corner) connector and chassis ground.

      Connector & terminal 

      (R364) No. 2 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes:  Go to  3 .

   No:  Repair or replace the short 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 ASSIST BRAKING (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2C12 displayed? (Current malfunction)

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

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