Communication For Initializing Impossible

When communication with the radar sensor is impossible

Detecting condition: 

• Defective harness connector
• Power supply circuit malfunction
• Defective radar sensor
• Defective CAN communication circuit
• Defective Subaru Select Monitor

Trouble symptom: 

Communication is impossible between radar sensor and Subaru Select Monitor.

Wiring diagram: 

SRVD system Refer to WIRING SYSTEM>BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK FUSE. 
   1. Turn the ignition switch to OFF.
   2. Check the fuse for radar sensor LH. Refer to BLIND SPOT DETECT ION/REAR CROSS TRAFFIC ALERT>RELAY AND FUSE .

      Is the check result OK?

      Yes:  Go to  2.

      No:  Replace the fuse. If the replaced fuse has blown out immediately, repair the short circuit to ground in harness between fuse and radar sensor LH.

2. CHECK HARNESS (OPEN CIRCUIT). 
   1. Disconnect the radar sensor LH connector.
   2. Turn the ignition switch to ON.
   3. Using a tester, measure the voltage between radar sensor LH connector (harness side) and chassis ground.

      Connector & terminal

      (R25) No. 5 (+) - Chassis ground (-):

      Is the voltage 10 V or more?

      Yes:  Go to  3.

      No:  Repair the open circuit of harness between fuse and radar sensor LH connector.

3. CHECK HARNESS (OPEN CIRCUIT). 
   1. Turn the ignition switch to OFF.
   2. Using a tester, measure the resistance between radar sensor LH connector (harness side) and chassis ground.

      Connector & terminal

      (R25) No. 10 - Chassis ground:

      Is the resistance less than 1 Ω?

      Yes:  Go to  4.

      No:  Repair the open circuit in harness between radar sensor and chassis ground.

4. CHECK LAN SYSTEM. 
   1. Connect the radar sensor LH connector.
   2. Inspect LAN system. Refer to BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

      Is the check result OK?

      Yes:  Go to  5.

      No:  Perform the inspection according to the diagnosis for LAN system.

5. CHECK RADAR SENSOR. 

   Communicate with the radar sensor.

   Is communication possible?

   Yes:  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.

   No:  Replace the radar sensor LH. Refer to BLIND SPOT DETECTION/REAR CROSS TRAFFIC ALERT>RADAR SENSOR .