VAG16839 (P0455) EVAP GROSS LEAK - 2001 VW Cabrio

This is an intermittent problem. The light comes on and I can't determine any specific cause, i.e., ambient conditions, driving conditions, etc. I have changed the fuel cap and inspected the connections/hoses within the engine compartment (haven't gotten to the tank connections). I am confused by the random nature of the fault; could it be in the pressure sensor in the system? Does anyone familar with the VW Cabrio EVAP system or VW in general have any ideas?

Thanks in advance.

how random is considered random?

I reset, it might go 2-3 days. Another time, I reset at night and the light came on 1/2 way to work. It has never came back on immediately after a reset.

You'll need to have it properly diagnosed by a shop with smoke machine unless you can locate a split vaccum line or something visually damaged like the cannister being cracked, etc

jeff is correct it's dealer and smoke test time. there are way to many things that can cause this problem. starting with a bad gas cap to a bad oring on the fuel/pump tank sender to a bad charcoal canister and hose eaten though by mice or road damage.

the only way to find it is with a smoke test to find the leak. sorry but i retired last year from vw and this is the only way to find and repair the problem