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 ECM.

Symptoms

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

P0451 HYUNDAI Description

The Evaporative Emission System (EVAP) control system pressure sensor detects pressure in the purge line. The sensor output voltage to the 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.