What are the common causes of P0451?

A failed EVAP pressure sensor. A short or open in the sensor wiring. Corrosion at the sensor connector. A clogged fuel tank vent valve. A failed fuel tank pressure sensor.

Compare the EVAP pressure reading to barometric on a scan tool. Check the sensor wiring for a short or open. Inspect the sensor connector for corrosion. Check the fuel tank vent valve for clogging. Replace the EVAP pressure sensor if the reading is off. Clear the code and retest.

P0451

EVAP System Pressure Sensor/Switch A Circuit Range/Performance

System: Auxiliary emission controls (P code)
Lamp: Check Engine Light
Category: Powertrain - Auxiliary Emissions Controls

What it means

P0451 means EVAP System Pressure Sensor/Switch A Circuit Range/Performance.

Where it lives

For P0451, the part to look at first is the sensor named here.

Check these first

A failed EVAP pressure sensor
A short or open in the sensor wiring
Corrosion at the sensor connector
A clogged fuel tank vent valve
A failed fuel tank pressure sensor

What to do next

Compare the EVAP pressure reading to barometric on a scan tool
Check the sensor wiring for a short or open
Inspect the sensor connector for corrosion
Check the fuel tank vent valve for clogging
Replace the EVAP pressure sensor if the reading is off
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.