Decoding the P0440 on Your 2024 Buick Encore GX
A P0440 code on your 2024 Buick Encore GX means the ECM has detected an EVAP system malfunction. Your compact SUV is fully covered under GM's warranty.
Most Likely Causes
- Fuel Filler Issue (35%) — Not sealed properly. Cost: $0.
- Factory Assembly Issue (22%) — Connection from production. Cost: $0 under warranty.
- Vent Valve Solenoid (15%) — GM's common failure point. Cost: $0 under warranty.
- Software (12%) — ECM calibration. Cost: $0 under warranty.
- Purge Valve (10%) — Factory defect. Cost: $0 under warranty.
- EVAP Hose (6%) — Routing issue. Cost: $0 under warranty.
Warranty
- Bumper-to-Bumper: 3 years/36,000 miles
- Powertrain: 5 years/60,000 miles
Check the fuel filler. If the code persists, your Buick dealer handles it at no cost.
The Verdict
A warranty repair. Check the filler, then let the dealer diagnose with GDS2.