I have a 1999 ML 430 that is bringing up a purge valve code. First of all is there only one purge valve? Where are they or it located? Can I get one from somewhere besides Mercedes (at Mercedes they're like 300). Thanks

 

I don't know exactly where it is in a 99 ML 430 but here is an article with a picture of one from another model. Hopefully, with it, you can find yours.

http://tinyurl.com/2am6p9w