P0497 Evap System Low Purge Flow, Stuck Closed

Code: P0497
Applies To: Most makes, generic code
Loose Cap Can Set It: Not named in our sources
Typical Fix: $210 to $251 at RepairPal

Too little fuel vapor is flowing from the canister into the engine.
A shop confirms it with the carmaker's EVAP test and a smoke machine before replacing parts.
Usually yes for now, but get it fixed soon and check for open recalls.

What The Carmakers Call It

EVAP System Low Purge Flow, stuck closed, as printed by Maserati S.p.A.

Causes Named In Carmaker Bulletins

Overfilling the tank plus a temperature swing of 20 F or more over about two days, which can soak EVAP parts with liquid fuel (2011 to 2015 Volt, 2014 to 2016 ELR) (source)
Check the purge valve connector and wiring (Maserati) (source)

No source ranks these by how often they happen, so they are listed as the bulletins give them.

No source ties P0497 to the gas cap.

What The Fix Costs

The usual part for this code is the purge valve. Published estimates put it at $210 to $251 at RepairPal. The full table with every source and date is on the cost page. A diagnosis first keeps you from paying for a part you did not need, which is why we price readiness monitors and smog check before the fix.

Getting The Light To Go Off

After the repair the light goes off once the EVAP test runs and passes on three drive cycles in a row, and the code is erased after 40 warm up cycles, per CARB. The test only runs under set conditions such as a fuel level between about 15 and 85 percent, so it can take days.