ENGINE (DIAGNOSTICS)(H4DOTC) > 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 servicing or replacing faulty parts, perform Clear Memory Mode and Inspection Mode

WIRING DIAGRAM:

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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

(B136) No. 8 — (F9) No. 13:

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 between ECM and chassis ground.

Connector & terminal

(B136) No. 8 — Chassis ground:

Is the resistance 1 MΩ or more?

Even if the malfunction indicator light illuminates, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

NOTE:

In this case, temporary poor contact of connector may be the cause.

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