Possible causes

– Lack of intake air volume (block air filter)
– Fuel injection system (Clogged fuel injector or bad fuel pump)
– Faulty Engine Control Module (ECM)

When is the code detected?

The P1421 code is detected when The Engine Control Module (ECM) does not control ignition timing and engine idle speed properly when engine is started with pre-warming up condition.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1421 INFINITI Description

The Engine Control Module (ECM) controls ignition timing and engine idle speed when engine is started with pre-warming up condition. This control promotes the activation of three way catalyst by heating the catalyst and reduces emissions.

INFINITI Technical Service Bulletins for P1421 code