The P0457 code on your 2021 Mazda CX-30 indicates an EVAP system leak detected, often specifically related to the fuel filler cap. This code is set when the ECM detects a leak and the fuel cap area is suspected or has been recently opened.
P0457 vs Other Leak Codes
While P0455 and P0456 indicate leak size, P0457 often indicates the leak is likely at the fuel cap or the cap was recently removed when the leak was detected. Some manufacturers set P0457 specifically when the cap appears to be the issue.
CX-30 EVAP Monitoring
The 2021 Mazda CX-30's Skyactiv engine includes sophisticated EVAP monitoring. The system tests for leaks and can sometimes identify that the filler cap area is the source based on when leaks are detected relative to refueling events.
Fuel Cap Related Issues
The cap may not have been tightened fully after refueling. The cap seal may be worn, cracked, or dirty. The cap's ratcheting mechanism may be worn, preventing proper seating. The filler neck may have debris preventing cap seating. The filler neck seal itself may be damaged.
Resolution Steps
Remove and reinstall the gas cap, ensuring it clicks multiple times to full tightness. Inspect the cap seal for cracks, dirt, or deformation. Clean the filler neck opening. If the cap appears worn, replace with an OEM Mazda cap. Clear codes and see if P0457 returns after several drive cycles.