Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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:
- Headlight system Ref. to WIRING SYSTEM>HEADLIGHT SYSTEM>WIRING DIAGRAM
- CAN communication system Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM
Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to FRONT RELAY CONTROL MODULE (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
.
- Turn the ignition switch to ON.
- Using the tester, measure the voltage between data link connector (i221) 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 (M/B fuse No. 2, F/B fuse No. 3)
- CHECK HARNESS BETWEEN DATA LINK CONNECTOR AND CHASSIS GROUND (OPEN)
.
- Turn the ignition switch to OFF.
- Using the tester, measure the resistance between data link connector (i221) 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.
Or, if the interface for Subaru Select Monitor is turned ON, Go to 4.
No : Repair the harness and connector.
If the interface for Subaru Select Monitor is not turned ON, replace the interface and harness for Subaru Select Monitor.
- CHECK INSTALLATION OF Front relay control module CONNECTOR
.
Check the Front relay control module connector.
Is the Front relay control module connectors (B68, B69) inserted into the Front relay control module until they lock?
Yes : Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE
No : Insert the Front relay control module connector to Front relay control module.
Or, repair the connector if it is faulty.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.