ENGINE (DIAGNOSTICS)(H4DOTC) > Diagnostics for Engine Starting Failure

IGNITION CONTROL SYSTEM

CAUTION:

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

WIRING DIAGRAM:

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1.CHECK SPARK PLUG CONDITION.

1) Remove the spark plug.

2) Check the spark plug condition.

Is the spark plug condition status normal?

Replace the spark plug.

2.CHECK IGNITION SYSTEM FOR SPARKS.

1) Connect the spark plug to ignition coil.

2) Release the fuel pressure.

3) Contact the spark plug thread portion to engine.

4) While opening the throttle valve fully, crank the engine to check that spark occurs at each cylinder.

Does spark occur at each cylinder?

Check fuel pump system.

3.CHECK POWER SUPPLY CIRCUIT FOR IGNITION COIL AND IGNITOR ASSEMBLY.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the ignition coil & ignitor assembly.

3) Turn the ignition switch to ON.

4) Measure the power supply voltage between ignition coil and ignitor assembly connector and engine ground.

Connector & terminal

(E31) No. 3 (+) — Engine ground (−):

(E32) No. 3 (+) — Engine ground (−):

(E33) No. 3 (+) — Engine ground (−):

(E34) No. 3 (+) — Engine ground (−):

Is the voltage 10 V or more?

Repair the harness and connector.

NOTE:

In this case, repair the following item:

Open circuit in harness between the ignition coil and ignitor assembly and ignition switch connector

Poor contact of coupling connector

4.CHECK HARNESS OF IGNITION COIL AND IGNITOR ASSEMBLY GROUND CIRCUIT.

1) Turn the ignition switch to OFF.

2) Measure the resistance between the ignition coil and ignitor assembly connector and engine ground.

Connector & terminal

(E31) No. 2 — (B137) No. 6:

(E31) No. 2 — (B137) No. 26:

(E32) No. 2 — (B137) No. 6:

(E32) No. 2 — (B137) No. 26:

(E33) No. 2 — (B137) No. 6:

(E33) No. 2 — (B137) No. 26:

(E34) No. 2 — (B137) No. 6:

(E34) No. 2 — (B137) No. 26:

Is the resistance less than 5 Ω?

Repair the harness and connector.

NOTE:

In this case, repair the following item:

Open circuit in harness between ignition coil and ignitor assembly connector, and ECM

5.CHECK HARNESS BETWEEN ECM AND IGNITION COIL AND IGNITOR ASSEMBLY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the ECM.

3) Disconnect the connector from the ignition coil & ignitor assembly.

4) Measure the resistance of harness between ECM and ignition coil and ignitor assembly connector.

Connector & terminal

(B137) No. 21 — (E34) No. 1:

(B137) No. 20 — (E33) No. 1:

(B137) No. 19 — (E32) No. 1:

(B137) No. 18 — (E31) 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 and ignition coil and ignitor assembly connector

Poor contact of coupling connector

6.CHECK HARNESS BETWEEN ECM AND IGNITION COIL AND IGNITOR ASSEMBLY CONNECTOR.

Measure the resistance of harness between ECM and engine ground.

Connector & terminal

(B137) No. 21 — Engine ground:

(B137) No. 20 — Engine ground:

(B137) No. 19 — Engine ground:

(B137) No. 18 — Engine ground:

Is the resistance 1 MΩ or more?

Repair the ground short circuit of harness between ECM and ignition coil and ignitor assembly connector.

7.CHECK POOR CONTACT.

Check poor contact of ECM connector.

Is there poor contact in ECM connector?

Repair the poor contact of ECM connector.

Check fuel pump circuit.