What does code P0440 mean on a Mazda and is it safe to drive?
P0440: Evaporative Emission System Control System Malfunction. Here's what it means on your Mazda, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
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What this code means
A general fault in the EVAP system—could be a leak, stuck valve, or sensor issue.
Common causes for your Mazda
- Gas cap loose or faulty
- Purge or vent valve stuck
- Charcoal canister or hose leak
Symptoms
- Check Engine Light
Typical fixes
- Replace gas cap
- Test purge/vent valves
- Smoke test EVAP system
Repair cost range
For a Mazda, repairs for P0440 often fall between $20 and $400, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Mazda
Mazda P0440 is typically the gas cap, purge solenoid, or a cracked EVAP line near the intake. The Mazda3 and Mazda6 have rubber EVAP hose connections that harden and crack with age—inspect all rubber hose connections before smoke testing.
Most commonly affected models
Mazda6 2003–2008Mazda3 2004–2009MPV 2000–2006