Volkswagen Repair: 2006 Passat 2.0 evaporator canister, diagnostic checkup, latter models

Question
My 2006 Passat (2.0, manual trans) with 59,000 miles had a check engine light come on - the check engine had come on before without any performance issues and would go go away after a day or so - this time though, it began to idle rough and felt like it was only running on 3 cylinders, lacking power when the tach was below 3,000.  The dealer said that the evaporator canister needed to be replaced at a cost of $883.00 and some other check valve that goes with it.  I am not feeling good about this one. What causes this part to fail?  Thanks - Dave


Answer
Hi David;
Unfortunately, the price of the EVAP canister in Volkswagens includes extra expense, because rather than making a cylindrical canister that take up alot of space, the canisters are moulded into shapes that fit into cavities in the bodywork of the car.  For example, in 1996 Jetta's have a canister behind the innnerfender liner of the right front wheelwell.  In 2000 Jetta's the canister fills a void behind the fender liner of the right rear wheelwell.  In addition to the special shape, the "leak detection pump" was included in the latter models' canister as well, instead of being separate, and taking up space elsewhere in the car.  None of this is designed to, nor does it make you feel any better about this repair, and I'm sorry about that.  This next thing may make you mad at me too, but I feel as if I need to say one more thing.  First, let me try to make you feel a little better by commending you for your complete question.  I am left to guess in many cases, and I appreciate the way you were concise(unlike me), and gave me much information with which to work.  This is a case where you needed to NOT discount the appearance of the check engine light, and take it to the dealer, for a complete diagnostic checkup, and if you had done so, there would be a record of your visits, and a good case for you to have the warranty, or dealer pay, instead of you.
Finally, the most common cause of failure is IMPACT.  They usually get damaged in small fender benders, because they are in voids that are close to the "skin."  Another common failure(in some models) is the leak detection pump fails.
I'm truly sorry to hear about your problem.  I hope I have shed some light on this issue, and answered your question completely.  Good luck, David.