P0440 on the Mazda CX-5: Meaning, Causes & Fix
Reviewed by the Wrenchit.ai editorial team · Last reviewed · Editorial standards
P0440 on the Mazda CX-5
We don't yet have a sourced, Mazda CX-5-specific note for P0440. The general causes below apply; ask Wrenchit AI with your year and engine for a ranking specific to your car.
Mazda CX-5 codes & symptoms · Mazda CX-5 recalls · Mazda CX-5 maintenance schedule
Causes ranked by likelihood
| Cause | Likelihood | DIY difficulty |
|---|---|---|
| Loose or faulty gas cap — Tighten or replace. | Most likely | 1/5 |
| EVAP hose leak — Visual inspection of rubber lines. | Possible | 1/5 |
| Bad purge valve — Common on older GM and Ford vehicles. | Less likely | 1/5 |
Symptoms of P0440
- CEL only
How to diagnose P0440
- Confirm the code. Read P0440 with an OBD-II scanner and note the freeze-frame data (speed, temperature, load) recorded when it set.
- Check for companion codes. Look for other stored or pending codes such as P0455, P0442 — they often point to one shared root cause.
- Check: Loose or faulty gas cap. Tighten or replace.
- Check: EVAP hose leak. Visual inspection of rubber lines.
- Check: Bad purge valve. Common on older GM and Ford vehicles.
- Clear and verify. After the repair, clear the code and complete a full drive cycle to confirm P0440 does not return.
Can I drive with P0440?
Yes, no drivability impact.
Related codes
Other codes on the Mazda CX-5
Frequently asked questions
What does P0440 mean on a Mazda CX-5?
P0440 means evaporative emission control system malfunction. P0440 is a generic EVAP system fault — your fuel vapor recovery system isn't sealing properly. Like P0455, the gas cap is the #1 culprit.
Can I drive with code P0440 on a Mazda CX-5?
Yes, no drivability impact.
What is the most common cause of P0440?
Loose or faulty gas cap — Tighten or replace.
What are the symptoms of P0440?
CEL only.
How much does it cost to fix P0440 on a Mazda CX-5?
A typical shop repair range is $0–$500, depending on which cause it turns out to be. Cheaper causes such as bad purge valve should be ruled out first.