Diagnostic Procedure for Subaru Select Monitor Communication: Inspection

Detecting condition: 

Defective harness connector

Trouble symptom: 

Communication is impossible between VDC and Subaru Select Monitor.

Wiring diagram: 

Vehicle dynamics control system Ref. to WIRING SYSTEM>VEHICLE DYNAMICS CONTROL SYSTEM .

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 Brake Control 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 VDCCM & H/U CONNECTOR. 

   Turn the ignition switch to OFF.

   Is the VDCCM & H/U connector inserted into VDCCM & H/U until the clamp locks onto it?

   Yes  : Go to  5.

   No  : Insert VDCCM & H/U connector into VDCCM & H/U.

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 VDC system can be executed normally.

   Is the [Select Function] screen displayed?

   Yes  : Check the DTC in VDC system. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   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 VDCCM & H/U connector and chassis ground.

      Connector and terminal 

      (B310) No. 1 (+) - Chassis ground (-):

      (B310) No. 30 (+) - Chassis ground (-):

      (B310) No. 35 (+) - Chassis ground (-):

   Is the voltage 10 - 15 V?

   Yes  : Go to  9.

   No  : Repair open circuit in harness between VDCCM & H/U and battery.

9. CHECK HARNESS CONNECTOR BETWEEN VDCCM & H/U AND CHASSIS GROUND. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the VDCCM & H/U.
   3. Measure the resistance of harness between VDCCM & H/U connector and chassis ground.

      Connector and terminal 

      (B310) No. 14 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes  : Go to  10.

   No  : Repair the open circuit of VDCCM & H/U ground circuit and poor contact of connector.

10. CHECK POOR CONTACT OF CONNECTOR. 

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

    Yes  : Repair the connector.

    No  : Replace the VDCCM & H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) .