AUTOMATIC TRANSMISSION (DIAGNOSTICS)(4AT)(D) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0725 ENGINE SPEED INPUT CIRCUIT

DTC DETECTING CONDITION:

Engine speed input signal circuit is open or shorted.

TROUBLE SYMPTOM:

• No lock-up occurs. (After engine is warmed-up)

• Power indicator light remains on when the vehicle speed is “0”.

WIRING DIAGRAM:

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1.CHECK HARNESS CONNECTOR BETWEEN TCM AND ECM.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from TCM and ECM.

3) Measure the resistance of harness between TCM and ECM.

Connector & terminal

2.0 L model

(B55) No. 11 — (B135) No. 25:

2.5 L model

(B55) No. 11 — (B136) No. 22:

Is the resistance less than 1 Ω?

Repair the open circuit of harness between TCM and ECM connector.

2.CHECK HARNESS CONNECTOR BETWEEN TCM AND ECM.

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

Connector & terminal

(B55) No. 11 — Chassis ground:

Is the resistance 1 MΩ or more?

Repair the short circuit of harness between TCM and ECM connector.

3.CHECK INPUT SIGNAL FOR TCM USING SUBARU SELECT MONITOR.

1) Connect the connectors to TCM and ECM.

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

3) Start the engine, and turn the Subaru Select Monitor power switch to ON.

4) Run the engine at idle.

5) Read the data of engine speed using Subaru Select Monitor.

Display shows engine speed signal value sent from ECM.

Is the revolution value same as the tachometer reading shown on the combination meter?

Even if the power indicator light is blinking, the circuit is in normal condition at this time. A temporary poor contact of connector or harness may be the cause. Repair the harness or connector in the TCM and ECM.

4.CHECK POOR CONTACT.

Is there poor contact in engine speed signal circuit?

Repair the poor contact.

5.CONFIRM DTC P0725.

Replace the ECM with a new part.

Does the DTC appear again, after the memory has been cleared?

Replace the TCM.

Replace the ECM.