What does code P0456 mean on a Ram and is it safe to drive?
P0456: Evaporative Emission System Leak Detected (Very Small Leak). Here's what it means on your Ram, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
What this code means
The EVAP system has detected a very small leak—often smaller than P0442. Commonly caused by a loose fuel cap or hairline crack in a hose.
Common causes for your Ram
- Loose or worn gas cap seal
- Hairline crack in EVAP hoses
- Minor leak at purge or vent valve fittings
Symptoms
- Check Engine Light only
- Usually no noticeable driving symptoms
Typical fixes
- Inspect and replace gas cap if seal is hardened or cracked
- Smoke-test EVAP system to locate tiny leaks
- Repair or replace leaking hoses and fittings
Repair cost range
For a Ram, repairs for P0456 often fall between $25 and $350, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Ram
Ram P0456 small EVAP leak is almost always the gas cap seal on these trucks. OEM Mopar caps are recommended—cheap aftermarket caps frequently fail to seal. If a new cap doesn't resolve it, the NVLD module hose is the next inspection point.
Most commonly affected models