Communication For Initializing Impossible

Diagnosis: 

Defective CAN communication circuit

Trouble symptom: 

• LAN system is abnormal.
• Communication failure between Subaru Select Monitor and A/C control panel

Wiring diagram: 

Air conditioning system Refer to WIRING SYSTEM>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK POWER SUPPLY CIRCUIT. 

   Connect DST-i to data link connector.

   Does DST-i turn ON?

   Yes:  Go to  4.

   No:  Go to  2.

2. CHECK POWER SUPPLY CIRCUIT. 

   Measure the voltage between data link connector and chassis ground.

   Connector & terminal 

   (B40) No. 16 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes:  Go to  3.

   No  Repair the power supply circuit.

   NOTE: In this case, repair the following item:

   • Open or ground short circuit of harness between battery and data link connector
   • Blown out of fuse (M/B No. 13)
3. CHECK HARNESS BETWEEN DATA LINK CONNECTOR AND CHASSIS GROUND (OPEN). 
   1. Turn the ignition switch to OFF.
   2. Measure the resistance of harness between data link connector and chassis ground.

   Connector & terminal 

   (B40) No. 4 - Chassis ground:

   (B40) No. 5 - Chassis ground:

   Is the resistance less than 5 Ω?

   Yes  Check for poor contact of the data link connector, and repair a fault, if any. When no fault is found, Go to  4.

   No  Repair the harness and connector.

4. CHECK SUBARU SELECT MONITOR. 
   1. Connect the Subaru Select Monitor to a normal vehicle.
   2. Start the engine and perform communication between the Subaru Select Monitor and vehicle.

   Is communication possible?

   Yes:  Go to  5.

   No  Use another Subaru Select Monitor because the CAN communication circuit of the Subaru Select Monitor is faulty.

5. CHECK LAN SYSTEM. 

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

   Is the check result of the LAN system OK?

   Yes:  Go to  6.

   No  Repair it according to the diagnosis for LAN system.

6. CHECK CONNECTOR. 

   Check for poor contact of power supply circuit connector.

   Is the check result OK?

   Yes:  Go to  7.

   No  Repair the connector.

7. CHECK FUSE. 
   1. Turn the ignition switch to OFF.
   2. Remove a fuse from the fuse box.
   3. Check the fuse.

   Is the check result OK?

   Yes:  Go to  8.

   No  Replace the fuse. If the replaced fuse blows out easily, repair the ground short circuit in harness between the A/C control panel - fuse.

8. CHECK A/C CONTROL PANEL POWER SUPPLY CIRCUIT (OPEN). 
   1. Disconnect the A/C control panel connector.
   2. Measure the voltage between A/C control panel connector terminal and chassis ground after turning the ignition switch to ON.

   Connector & terminal 

   (i88) No. 15 (+) - Chassis ground (-):

   (i88) No. 31 (+) - Chassis ground (-):

   (i88) No. 32 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes:  Go to  9.

   No  Check for open or short circuit in the harness between A/C control panel and fuse.

9. CHECK A/C CONTROL PANEL GROUND CIRCUIT (OPEN). 

   Measure the resistance of harness between A/C control panel and chassis ground.

   Connector & terminal 

   (i88) No. 34 - Chassis ground:

   Is the resistance less than 5 Ω?

   Yes  Recheck the poor contact between the data link connector and select monitor.

   No  Repair the harness for ground line.