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Subaru Legacy Service Manual: Check power supply and ground line of engine control module (ecm)

Subaru Legacy Service Manual / Engine (diagnostics)(h4do) / Diagnostics for engine starting failure / Check power supply and ground line of engine control module (ecm)

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and Inspection Mode Inspection Mode > PROCEDURE.

WIRING DIAGRAM:

Engine Electrical System ENGINE TYPE FB (WITHOUT PUSH BUTTON START) Engine Electrical System > WIRING DIAGRAM

Engine Electrical System ENGINE TYPE FB (WITH PUSH BUTTON START) Engine Electrical System > WIRING DIAGRAM

STEPCHECKYESNO

1.CHECK M/B (MAIN RELAY).

1) Turn the ignition switch to OFF.

2) Remove the M/B (main relay).

3) Connect the battery to M/B (main relay) terminals No. 2 and No. 4.

4) Measure the resistance between M/B (main relay) terminals.

Terminals

No. 1 — No. 3:

Is the resistance less than 1 --

Diagnostics for Engine Starting Failure > CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM)

Replace the M/B (main relay). Main Relay

2.CHECK GROUND CIRCUIT FOR ECM.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between ECM connector and chassis ground.

Connector & terminal

(E158) No. 61 — Chassis ground:

(E158) No. 62 — Chassis ground:

(E158) No. 63 — Chassis ground:

(E158) No. 64 — Chassis ground:

(E158) No. 65 — Chassis ground:

Is the resistance less than 5 --

Diagnostics for Engine Starting Failure > CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM)

Open circuit of harness between ECM connector and engine ground terminal

3.CHECK INPUT VOLTAGE OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connector and chassis ground.

Connector & terminal

(B134) No. 2 (+) — Chassis ground (−):

(B134) No. 27 (+) — Chassis ground (−):

Is the voltage 10 V or more-

Diagnostics for Engine Starting Failure > CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM)

Repair the open or ground short in the harness of power supply circuit.

4.CHECK M/B (MAIN RELAY) INPUT VOLTAGE.

Measure the voltage between M/B (main relay) terminal and chassis ground.

Terminals

No. 1 (+) — Chassis ground (−):

No. 2 (+) — Chassis ground (−):

Is the voltage 10 V or more-

Diagnostics for Engine Starting Failure > CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM)

Repair the open or ground short in the harness of power supply circuit.

5.CHECK INPUT VOLTAGE OF ECM.

1) Turn the ignition switch to OFF.

2) Install the M/B (main relay).

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connector and chassis ground.

Connector & terminal

(B134) No. 60 (+) — Chassis ground (−):

Is the voltage 10 V or more-

Diagnostics for Engine Starting Failure > CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM)

Repair the open circuit of harness between ECM connector and M/B (main relay) terminal.

6.CHECK INPUT VOLTAGE OF ECM.

1) Turn the ignition switch to OFF.

2) Connect the connector to ECM.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connector and chassis ground.

Connector & terminal

(B134) No. 1 (+) — Chassis ground (−):

(B134) No. 14 (+) — Chassis ground (−):

Is the voltage 10 V or more-

Check ignition control system. Diagnostics for Engine Starting Failure > IGNITION CONTROL SYSTEM

Repair the harness and connector.

NOTE:

In this case, repair the following item:

Open circuit of harness between ECM connector and M/B (main relay) connector

Poor contact of M/B (main relay) connector

Poor contact of ECM connector

Fuel injector circuit
CAUTION:• Check or repair only faulty parts.• After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and Inspection Mode Inspection Mode > PR ...

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CAUTION:After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and Inspection Mode Inspection Mode > PROCEDURE.WIRING DIAGRAM:• Engine Electrical S ...

Other materials:

Adjustment
1. THRUST BEARING PRELOAD1. Select a suitable adjusting washer No. 1 so that dimension (H) will be zero in a visual check. Position the washer (20 - 31 - 4) and lock washer (20 - 31 - 2.3) and attach the lock nut (20 - 11).2. Install the lock nut with ST1, ST2 and ST3.NOTE:• Use new lock nuts ...

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