Possible causes

– Faulty Evaporative Emission System (EVAP) Pressure Sensor
– Evaporative Emission System (EVAP) Pressure sensor harness is open or shorted
– Evaporative Emission System (EVAP) Pressure sensor circuit poor electrical connection
– Faulty Engine Control Module (ECM)

When is the code detected?

An improper voltage signal from EVAP control system pressure sensor is sent to Engine Control Module (ECM).

Symptoms

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

P0451 NISSAN Description

The Evaporative Emission System (EVAP) control system pressure sensor detects pressure in the purge line. The sensor output voltage to the Engine Control Module (ECM) increases as pressure increases. The EVAP control system pressure sensor is not used to control the engine system. It is used only for on board diagnosis.

NISSAN Technical Service Bulletins for P0451 code