Diagnostic Procedure for Subaru Select Monitor Communication: Inspection

Trouble symptom: 

Cannot communicate with [Multi-Function Display].

Detecting condition: 

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

Wiring diagram: 

• Multi-function display (MFD) system Ref. to WIRING SYSTEM>MULTI-FUNCTION DISPLAY (MFD) SYSTEM>WIRING DIAGRAM .
• CAN communication system Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK IGNITION SWITCH. 

   Check the ignition switch.

   Is the ignition switch ON?

   Yes:  Go to  2.

   No:  Turn the ignition switch to ON, and select the [Multi-Function Display] using the Subaru Select Monitor.

2. CHECK BATTERY. 
   1. Turn the ignition switch to OFF.
   2. Check the battery. Ref. to STARTING/CHARGING SYSTEMS (H4DO)>BATTERY>INSPECTION .

   Is the check result OK?

   Yes:  Go to  3.

   No:  Charge or replace the battery.

3. CHECK INSTALLATION OF MFD CONNECTOR. 

   Check the MFD connector.

   Is the MFD connector inserted into the MFD until it locks?

   Yes:  Go to  4.

   No:  Be sure to insert the MFD connector into the MFD until it is locked.

4. CHECK LAN SYSTEM. 

   Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

   Is there any fault in LAN system?

   Yes:  Perform the inspection according to the diagnosis for LAN system.

   No:  Go to  5.

5. CHECK SUBARU SELECT MONITOR COMMUNICATION. 
   1. Turn the ignition switch to ON.
   2. Check whether communication to MFD can be executed normally.

   Is communication with [Multi-function Display] possible?

   Yes:  Read the DTC of [Multi-Function Display] using the Subaru Select Monitor. Ref. to MULTI-FUNCTION DISPLAY (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   No:  Go to  6.

6. CHECK SUBARU SELECT MONITOR. 

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

   Is communication for initializing possible?

   Yes:  Go to  7.

   No:  Repair or replace the Subaru Select Monitor.

7. CHECK MFD POWER SUPPLY CIRCUIT (OPEN OR SHORT CIRCUIT). 
   1. Turn the ignition switch to OFF.
   2. Disconnect the MFD connector.
   3. Turn the ignition switch to ON.
   4. Using a tester, measure the voltage between the MFD connector and chassis ground.

   Connector & terminal 

   (i122) No. 23 (+) - Chassis ground (-):

   (i122) No. 24 (+) - Chassis ground (-):

   Is the voltage 10 - 16 V?

   Yes:  Go to  8.

   No:  Repair the open or short circuit of harness, or poor contact of connector.

8. CHECK MFD GROUND CIRCUIT (OPEN). 
   1. Turn the ignition switch to OFF.
   2. Measure the resistance between MFD connector and chassis ground.

   Connector & terminal 

   (i122) No. 21 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  Go to  9.

   No:  Repair the open circuit of the MFD ground circuit or poor contact of connector.

9. CHECK POOR CONTACT OF CONNECTOR. 

   Check MFD power supply, ground circuit and data link connector for poor contact.

   Is there poor contact?

   Yes:  Repair the poor contact.

   No:  Replace the MFD. Ref. to INSTRUMENTATION/DRIVER INFO>MULTI-FUNCTION DISPLAY (MFD) .