AUTOMATIC TRANSMISSION (DIAGNOSTICS)(4AT) > Diagnostic Procedure without Diagnostic Trouble Code (DTC)

CHECK FWD SWITCH

DIAGNOSIS:

FWD signal circuit is open or shorted.

TROUBLE SYMPTOM:

LED does not illuminate even if FWD switch is ON.

WIRING DIAGRAM:

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1.CHECK INDICATOR.

Turn the ignition switch to ON.

Is the AWD warning light illuminated?

Perform the self-diagnosis of combination meter.

2.CHECK INDICATOR.

Turn the ignition switch to ON and wait for at least 2 seconds.

Is the AWD warning light illuminated?

3.CHECK INDICATOR.

Start the engine and wait for 2 seconds or more.

Does the AWD warning light go off?

4.CHECK SPARE FUSE.

Is the spare fuse OK?

Replace the fuse.

5.CHECK INDICATOR.

1) Turn the ignition switch to OFF.

2) Install a fuse to the FWD fuse holder.

3) Start the engine and wait for 2 seconds or more.

Is the AWD warning light illuminated?

Normal. Finish the diagnosis.

6.CHECK BODY INTEGRATED UNIT.

Is DTC of CAN communication displayed?

Perform the diagnosis according to DTC.

7.CHECK TCM.

1) Turn the ignition switch to OFF.

2) Install a fuse to the FWD fuse holder.

3) Connect the Subaru Select Monitor to data link connector.

4) Turn the ignition switch to ON.

5) Read the data of “FWD Switch” using Subaru Select Monitor.

Is “ON” displayed?

Perform the self-diagnosis of combination meter.

8.CHECK HARNESS CONNECTOR BETWEEN TCM AND FUSE BOX.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from TCM and fuse box.

3) Measure the resistance of the harness between TCM and fuse box.

Connector & terminal

(B54) No. 10 — (B158) No. 7:

Is the resistance less than 1 Ω?

Repair the open circuit of harness between TCM and fuse box.

9.CHECK HARNESS CONNECTOR BETWEEN FUSE BOX AND CHASSIS GROUND.

Measure the resistance of the harness between fuse box and chassis ground.

Connector & terminal

(i5) No. 13 — Chassis ground:

Is the resistance less than 1 Ω?

Repair the open circuit of harness between fuse box and chassis ground.

10.CHECK FOR POOR CONTACT.

Check poor contact of FWD switch circuit.

Is there poor contact of FWD switch circuit?

Repair the poor contact.

Replace the TCM.

11.CHECK TCM.

1) Turn the ignition switch to OFF.

2) Connect the Subaru Select Monitor to data link connector.

3) Start the engine.

4) Read the data of “Engine Speed” using Subaru Select Monitor.

Is the measured value 400 rpm or more?

Inspect the ECM.

12.CHECK TCM.

Read the data of “FWD Switch” using Subaru Select Monitor.

Is “OFF” displayed?

Perform the self-diagnosis of combination meter.

13.CHECK HARNESS CONNECTOR BETWEEN TCM AND FUSE BOX.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from TCM and fuse box.

3) Measure the resistance of harness connector between TCM and chassis ground.

Connector & terminal

(B54) No. 10 — Chassis ground:

Is the resistance 1 MΩ or more?

Replace the TCM.

Repair the short circuit of harness between TCM and fuse box.