Diagnostic Procedure for Subaru Select Monitor Communication: Inspection

When communication with DCM is impossible

Detecting condition: 

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

Trouble symptom: 

Communication is impossible between DCM and Subaru Select Monitor.

Wiring diagram: 

• Telematics Ref. to WIRING SYSTEM>TELEMATICS SYSTEM>WIRING DIAGRAM
• CAN communication system Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK FUSE  .
   1. Turn the ignition switch to OFF.
   2. Check the fuse of the DCM. Ref. to WIRING SYSTEM>TELEMATICS SYSTEM>WIRING DIAGRAM

   Is the check result OK?

   Yes  : Go to  2.

   No  : Replace the fuse. If the replaced fuse blows out easily, repair the ground short circuit in harness between the fuse - DCM connector.

2. CHECK FOR OPEN CIRCUIT IN THE POWER SUPPLY CIRCUIT  .
   1. Disconnect the DCM connector.
   2. Turn the ignition switch to ON.
   3. Using a tester, measure the voltage between DCM connector (harness side) and the chassis ground.

      Connector & terminal 

      (i105) No. 8 (+) - Chassis ground (-):

      (i105) No. 10 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes  : Go to  3.

   No  : Repair the open circuit in the wiring harness between fuse and DCM connector.

3. CHECK FOR OPEN CIRCUIT IN HARNESS BETWEEN DCM CONNECTOR AND CHASSIS GROUND  .
   1. Turn the ignition switch to OFF.
   2. Using a tester, measure the resistance between DCM connector (harness side) and the chassis ground.

      Connector & terminal 

      (i105) No. 14 - Chassis ground:

   Is the resistance 1 Ω or less?

   Yes  : Go to  4.

   No  : Repair the open circuit in harness between DCM connector and chassis ground.

4. CHECK LAN SYSTEM  .

   Inspect LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE

   Is the check result OK?

   Yes  : Go to  5.

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

5. CHECK TELEMATICS  .
   1. Turn the ignition switch to ON.
   2. Communicate with [Telematics] using the Subaru Select Monitor.

   Is communication possible?

   Yes  : 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. 

   No  : Replace the DCM. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE