Diagnostic Procedure for Subaru Select Monitor Communication: Inspection

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.

Detecting condition:

Defective harness
Power supply circuit malfunction
Defective TPMS & keyless entry control module or TPMS Control Module
Defective CAN communication circuit
Defective Subaru Select Monitor

Trouble symptom:

Not communicable with Subaru Select Monitor.

Wiring diagram:

Tire pressure monitoring system Ref. to WIRING SYSTEM>TIRE PRESSURE MONITORING SYSTEM>WIRING DIAGRAM
CAN communication system Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to TIRE PRESSURE MONITOR (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION

CHECK POWER SUPPLY CIRCUIT .
Connect the interface for Subaru Select Monitor to the data link connector.

Does the interface for Subaru Select Monitor turn on?

Yes : Go to 4.

No : Go to 2.
CHECK POWER SUPPLY CIRCUIT .
1. Turn the ignition switch to ON.
2. Using the tester, measure the voltage between data link connector and chassis ground.
  Connector & terminal
  
  (i221) No. 8 (+) - Chassis ground (-):
  
  (i221) 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
CHECK HARNESS BETWEEN DATA LINK CONNECTOR AND CHASSIS GROUND (OPEN) .
1. Turn the ignition switch to OFF.
2. Using the tester, measure the resistance between data link connector and chassis ground.
  Connector & terminal
  
  (i221) No. 4 - Chassis ground:
  
  (i221) 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.
CHECK SUBARU SELECT MONITOR .
1. Connect the Subaru Select Monitor to a normal vehicle.
2. Start the engine and establish 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.
CHECK LAN SYSTEM .
Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE

Is the check result OK?

Yes : Go to 6.

No : Perform the inspection according to the diagnosis for LAN system.
CHECK CONNECTOR .
Check for poor contact of TPMS & keyless entry control module or TPMS Control Module connector, data link connector, or intermediate connector.

Is the check result OK?

Yes : Go to 7.

No : Repair the connector.
CHECK FUSE .
1. Turn the ignition switch to OFF.
2. Check the fuse. Ref. to WIRING SYSTEM>TIRE PRESSURE MONITORING SYSTEM>WIRING DIAGRAM
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 TPMS & keyless entry control module or TPMS Control Module connector and fuse.
CHECK TPMS & KEYLESS ENTRY CONTROL MODULE OR TPMS CONTROL MODULE CONNECTOR POWER SUPPLY CIRCUIT (OPEN) .
1. Disconnect the connector of the TPMS & keyless entry control module or TPMS Control Module.
2. Turn the ignition switch to ON.
3. Measure the voltage between TPMS & keyless entry control module or TPMS Control Module connector and chassis ground.
  Connector & terminal
  
  (L83) No. 6 (+) - Chassis ground (-):
  
  (L83) No. 12 (+) - Chassis ground (-):
Is the voltage 10 V or more?

Yes : Go to 9.

No : Check for open or short circuit in the harness between TPMS & keyless entry control module or TPMS Control Module connector and fuse.
CHECK TPMS & KEYLESS ENTRY CONTROL MODULE OR TPMS CONTROL MODULE GROUND CIRCUIT (OPEN) .
Measure the resistance of harness between TPMS & keyless entry control module or TPMS Control Module connector and chassis ground.

Connector & terminal

(L83) No. 7 - Chassis ground:

Is the resistance less than 1 Ω?

Yes : Check the connection between the data link connector and Subaru Select Monitor.

No : Repair the harness for ground line.