ENGINE (DIAGNOSTICS)(H4SO) > Diagnostics for Engine Starting Failure

FUEL INJECTOR CIRCUIT

CAUTION:

• Check or repair only faulty parts.

• After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

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1.CHECK OPERATION OF EACH FUEL INJECTOR.

While cranking the engine, check each fuel injector emits operating sound. Use a sound scope or attach a screwdriver to the injector and hear for this check.

Does the fuel pump emit operating sound?

Check the fuel pressure.

2.CHECK POWER SUPPLY TO EACH FUEL INJECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector.

3) Turn the ignition switch to ON.

4) Measure the voltage between fuel injector connector and the engine ground.

Connector & terminal

#1 (E5) No. 2 (+) — Engine ground (−):

#2 (E16) No. 2 (+) — Engine ground (−):

#3 (E6) No. 2 (+) — Engine ground (−):

#4 (E17) No. 2 (+) — Engine ground (−):

Is the voltage 10 V or more?

Repair the harness and connector.

NOTE:

In this case, repair the following item:

• Open circuit of harness between main relay and fuel injector connector

• Poor contact of main relay connector

• Poor contact of coupling connector

3.CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the ECM.

3) Measure the resistance of harness between ECM connector and fuel injector connector.

Connector & terminal

#1 (B137) No. 8 — (E5) No. 1:

#2 (B137) No. 9 — (E16) No. 1:

#3 (B137) No. 10 — (E6) No. 1:

#4 (B137) No. 11 — (E17) No. 1:

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 connector and fuel injector connector

• Poor contact of coupling connector

4.CHECK HARNESS BETWEEN ECM AND FUEL INJECTOR CONNECTOR.

Measure the resistance of harness between ECM connector and fuel injector connector.

Connector & terminal

#1 (B137) No. 8 — Chassis ground:

#2 (B137) No. 9 — Chassis ground:

#3 (B137) No. 10 — Chassis ground:

#4 (B137) No. 11 — Chassis ground:

Is the resistance 1 MΩ or more?

Repair the short circuit to ground in harness between ECM connector and fuel injector connector.

5.CHECK EACH FUEL INJECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between each fuel injector terminals.

Terminals

No. 1 — No. 2:

Is the resistance between 5 — 20 Ω?

Replace the faulty fuel injector.

6.CHECK FOR POOR CONTACT.

Check for poor contact of the ECM connector.

Is there poor contact in ECM connector?

Repair the poor contact of the ECM connector.

Inspection using “General Diagnostic Table”