ENGINE (DIAGNOSTICS)(H4SO) > Diagnostic Procedure for Subaru Select Monitor Communication

COMMUNICATION FOR INITIALIZING IMPOSSIBLE

DIAGNOSIS:

Open or short circuit in data link connector

TROUBLE SYMPTOM:

Subaru Select Monitor communication failure

WIRING DIAGRAM:

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1.CHECK POWER SUPPLY CIRCUIT.

Connect the SDI (Subaru Diagnosis Interface) or general scan tool to data link connector.

Does SDI or general scan tool turn ON?

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?

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.

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?

Repair the poor contact of data link connector.

Repair the harness and connector.

NOTE:

In this case, repair the following item:

Open circuit of harness between ECM and data link connector

Open circuit of harness between ECM and engine ground

Poor contact in ECM connector

Poor contact of coupling connector

4.CHECK HARNESS BETWEEN ECM AND DATA LINK CONNECTOR.

1) Disconnect the connector from ECM, TCM, VDC CM, airbag CM and body integrated unit.

CAUTION:

When disconnecting the connector from airbag control module, always follow the precautions on AB section.

2) Measure the resistance of harness between ECM and data link connector.

Connector & terminal

(B136) No. 16 — (B40) No. 7:

Is the resistance less than 1 Ω?

Repair the harness and connector.

NOTE:

In this case, repair the following item:

Open circuit of harness between ECM and data link connector

Poor contact of coupling connector (LHD model)

5.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?

Repair the poor contact in the ECM or data link connector.

Repair the ground short circuit of harness between ECM and data link connector.