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.
Communication For Initializing Impossible
Diagnosis:
Open or short circuit in data link connector
Trouble symptom:
Subaru Select Monitor communication failure
Wiring diagram:
Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .
- CHECK POWER SUPPLY CIRCUIT
.
Connect DST-i or a general scan tool to the data link connector.
Is the DST-i or the general scan tool turned to ON?
Yes: Go to 4.
No: GO to 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)
- CHECK HARNESS BETWEEN DATA LINK CONNECTOR AND CHASSIS GROUND
.
- Turn the ignition switch to OFF.
- 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: Repair the poor contact of data link connector.
NO: Repair the harness and connector.
NOTE: In this case, repair the following item:- Open circuit in harness between ECM connector and data link connector
- Open circuit of harness between ECM connector and engine ground
- Poor contact of ECM connector
- Poor contact of joint connector
- CHECK HARNESS BETWEEN ECM AND DATA LINK CONNECTOR
.
- Disconnect the connectors from ECM, DCCD CONTROL MODULE, VDC CONTROL MODULE, airbag CONTROL MODULE, impact sensor, TPMS & keyless entry CONTROL MODULE, and body integrated unit.CAUTION: When disconnecting the connector from airbag CONTROL MODULE, always follow the precautions on AB article. Ref. to AIRBAG SYSTEM>General Description>CAUTION .
- Measure the resistance of harness between ECM connector and data link connector.
Connector & terminal
(B135) No. 14 - (B40) No. 7:
Is the resistance less than 1 Ω?
Yes: Go to 5.
No: Repair the open circuit of harness between ECM connector and data link connector.
- Disconnect the connectors from ECM, DCCD CONTROL MODULE, VDC CONTROL MODULE, airbag CONTROL MODULE, impact sensor, TPMS & keyless entry CONTROL MODULE, and body integrated unit.
- CHECK HARNESS BETWEEN ECM AND DATA LINK CONNECTOR
.
Measure the resistance between data link connector and chassis ground.
Connector & terminal
(B40) No. 7 - Chassis ground:
Is the resistance 1 MΩ or more?
Yes: Repair the poor contact of ECM connector or data link connector.
No: Repair the short circuit to ground in harness between ECM connector and data link connector.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.