I just happened to be browsing the Tech Help forum and found this currently active thread about the same problem:

http://www.peachparts.com/shopforum/showthread.php?threadid=55328


In particular, look at the post by mercedesmatt about vacuum. That sounds like the problem in your case.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
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