Diagnostic Procedure For Subaru Select Monitor Communication: Inspection

Trouble symptom: 

Communication with Front relay control module is impossible.

Detecting condition: 

• Defective harness connector
• Power supply circuit malfunction
• Front relay control module malfunctioning
• Defective CAN communication circuit
• Defective Subaru Select Monitor

Wiring diagram: 

CAN communication system Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK IGNITION SWITCH  .

   Is the ignition switch ON?

   Yes:  Go to  2 .

   No:  Turn the ignition switch to ON, and select the [Front Relay Control Module] using the Subaru Select Monitor.

2. CHECK BATTERY  .
   1. Turn the ignition switch to OFF.
   2. Measure the battery voltage.

      Is the voltage 11 V or more?

      Yes:  Go to  3 .

      No:  Charge or replace the battery.

3. CHECK BATTERY TERMINAL  .

   Is there poor contact at battery terminal?

   Yes:  Replace or tighten the battery terminal.

   No:  Go to  4 .

4. CHECK INSTALLATION OF Front relay control module CONNECTOR  .

   Turn the ignition switch to OFF.

   Is the Front relay control module connectors (B68, B69) inserted into the Front relay control module until they lock?

   Yes:  Go to  5 .

   No:  Insert the Front relay control module connector to Front relay control module.

5. CHECK LAN SYSTEM  .

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

   Is the check result OK?

   Yes:  Go to  6 .

   No:  Perform the diagnosis for LAN system.

6. CHECK SUBARU SELECT MONITOR COMMUNICATION  .
   1. Turn the ignition switch to ON.
   2. Check whether communication to the Front relay control module can be executed normally.

      Is the [Select Function] screen displayed?

      Yes:  Check the Front relay control module DTC. Ref. to FRONT RELAY CONTROL MODULE (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)>LIST .

      No:  Go to  7 .

7. CHECK SUBARU SELECT MONITOR COMMUNICATION  .

   Connect the Subaru Select Monitor to another vehicle to check whether the communication for initializing can be executed normally.

   Does the Subaru Select Monitor communicate normally?

   Yes:  Go to  8 .

   No:  Repair or replace the Subaru Select Monitor.

8. CHECK POWER SUPPLY CIRCUIT  .
   1. Turn the ignition switch to ON. (Engine OFF)
   2. Measure the ignition power supply voltage between the Front relay control module connectors (B68, B69) and chassis ground.

      Connector & terminal 

      (B68) No. 5 (+) - Chassis ground (-):

      (B69) No. 10 (+) - Chassis ground (-):

      (B69) No. 11 (+) - Chassis ground (-):

      Is the voltage 10 - 15 V?

      Yes:  Go to  9 .

      No:  Repair the open circuit of harness between Front relay control module and battery.

9. CHECK HARNESS CONNECTOR BETWEEN Front relay control module AND CHASSIS GROUND  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from Front relay control module.
   3. Measure the resistance of harness between the Front relay control module connectors (B68, B69) and chassis ground.

      Connector & terminal 

      (B68) No. 3 - Chassis ground:

      (B69) No. 12 - Chassis ground:

      Is the resistance less than 10 Ω?

      Yes:  Go to  10 .

      No:  Repair the open circuit of Front relay control module ground circuit and the poor contact of connector.

10. CHECK POOR CONTACT OF CONNECTOR  .

    Is there poor contact in Front relay control module power supply, ground circuit and data link connector?

    Yes:  Repair the connector.

    No:  Replace Front relay control module. Ref. to BODY CONTROL/COMMUNICATION SYSTEM>FRONT RELAY CONTROL MODULE .