P0451 on a Chevy: Causes, Fixes & Repair Cost

🟢 Low severity · drivable

You can keep driving a Chevy with P0451 — it's an emissions fault, not an engine problem — but fix it before your next emissions test.

What P0451 means on a Chevy

On a Chevy, P0451 means the fuel tank pressure sensor in the EVAP system is reporting a reading that's outside the expected range. The sensor monitors tank pressure so the computer can run its evaporative emissions test. A bad reading turns on the check engine light without affecting how the vehicle drives.

Is P0451 common on Chevys?

P0451 shows up on Chevys as the fuel tank pressure sensor ages, most often on higher-mileage Silverados, Equinoxes, and Malibus. Corroded wiring and a sticking vent valve are also common causes. It is an emissions fault, not a drivability fault.

Commonly reported on: Silverado, Equinox, Malibu, Traverse.

Symptoms

Check engine light on
Possible faint fuel smell
No change in how the vehicle drives

Common causes

most common: Faulty fuel tank pressure sensor
common: Corroded or damaged wiring
common: Stuck or faulty EVAP vent valve
less common: Cracked EVAP hose

How to fix it

Fix	DIY?	Typical cost
Inspect the sensor wiring and connector	Yes	$10–50
Replace the fuel tank pressure sensor	Yes	$90–250
Have a smoke test done if the code returns	Mechanic	$50–150