P1421 Code failures by brands


Description of DTC code P1421

The ECM (Engine Control Module) manages and regulates all the engine systems to achieve maximum engine performance. It handles some things such as the ignition timing and engine idle speed once the engine is started during warm-up conditions. This control activates the catalytic converter, which reduces emissions when it is warmed up.

On Nissan and Infiniti vehicles, the diagnostic code P1421 OBDII is stored when the Engine Control Module cannot properly control the ignition timing and idle speed when the engine is started under warm-up conditions.

Symptoms of fault code P1421

Causes of OBD2 P1421

Reasons why the P1421 OBD2 fault code is set:

  • The air filter could be blocked, causing a lack of intake air volume.
  • The fuel system may be damaged by a clogged fuel injector or a bad fuel pump.
  • The Motor Control Module may be faulty.

Possible solutions of the DTC code P1421

Steps to solve the OBDII DTC P1421:

  • Consult the manufacturer's information source for Technical Service Bulletins.
  • Check with a scanner to know if there are additional DTCs set in addition to P1421. If so, diagnose them in the order shown by the scanner.
  • Check the air cleaner for clogs that could cause the intake air system to fail. Repair as necessary.
  • Check the fuel pump and injectors for common damage such as blockage or other conditions. Make any necessary corrections.

Codes related to P1421

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