What can cause shut off valve failure?
 

I had a P0455 code. They made a vacuum test and there was no vacuum at all. Then they triggered the valve a couple of times, and then the vacuum was ok. They weren't able to reproduce the problem.

The thing is that last time I had that exact same problem, they changed the shut off valve (probably they did not have to)

The MB tech at the dealer passed 3.5 hours on the problem and could not find anything

Does someone have an idea of what other cause could do this problem? Maybe a connection to the valve?

Thanks

Etienne

Code P0 455 (large leak!) means that when the fuel evap system is tested it doesn't hold any vacuum/pressure. There are 4 different componets in that system (depends on year & model!!) that can cause that code. Starts underhood with the purge valve. Goes back to the purge switch-over valve. The MAP sensor in the fuel tank sending unit monitors vacuum/pressure changes, & last is the intergrity of the fuel tank & hoses. OF course the fuel cap as well!
ANY of those can & do cause that code!

wow thanks for that precise info

my car is a 2000 C230 kompressor

the report says that there was zero vacuum on the shut off valve, then they triggered it a couple of times and after that it went fine.

I will see how long it works before doing it again.

Etienne