ENGINE (DIAGNOSTICS)(H4DO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0418 SECONDARY AIR INJECTION SYSTEM CONTROL “A” CIRCUIT

DTC DETECTING CONDITION:

Immediately at fault recognition

CAUTION:

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

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK HARNESS BETWEEN ECM AND SECONDARY AIR PUMP RELAY.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the ECM and secondary air pump relay.

3) Measure the resistance of the harness between the ECM and secondary air pump relay.

Connector & terminal

(B135) No. 5 — (F9) No. 6:

Is the resistance less than 1 Ω?

Repair open circuit of the harness between the ECM and secondary air pump relay.

2.CHECK HARNESS BETWEEN ECM AND SECONDARY AIR PUMP RELAY.

Measure the resistance of harness between ECM and chassis ground.

Connector & terminal

(B135) No. 5 — Chassis ground:

Is the resistance 1 MΩ or more?

Temporary poor contact occurs. Check the poor contact of connector.

Repair ground short of the harness between the ECM and secondary air pump relay.