P0440

What P0440 means

The EVAP system captures fuel vapors from the tank and feeds them to the engine instead of venting them. P0440 is a generic 'something in EVAP is wrong' code; it's often set alongside more specific codes like P0442 or P0455.

Symptoms

• Check engine light
• Slight fuel smell (rare)
• No drivability issue

Likely causes (most common first)

1. Loose or cracked fuel cap (free fix — check here first)
2. Cracked EVAP hose
3. Failed EVAP purge or vent valve
4. Cracked charcoal canister

Can I keep driving?

Low — mostly emissions/economy

Typical repair cost

DIY fixes can start near $0 (parts only). Shop repairs for P0440 typically run up to $400 depending on the underlying cause and vehicle. Start with the most common cause — Loose or cracked fuel cap (free fix — check here first) — before throwing parts at it.

Symptoms that match P0440

If you got here from a search query, one of these might describe what your car is actually doing:

• "Check Gas Cap" Message — Easy Fix

Related codes

Confirm P0440 yourself in 60 seconds

AXLY.pro is a free iPhone app that pairs with any Bluetooth OBD2 adapter to read P0440 and every other stored code, plus live engine data. No subscription.