My 2014 Jetta TDI has been throught the mill at the local VW dealer shop to fix 3 things to pass the CA smog test. One flop after another for 2 months, but all fixed now, except the check engine light is back on. This happened last summer as well and after keeping it for 2 weeks they still couldn't figure it out. Told me it was OK to drive. (It actually wasn't but that's another story). I need an experienced TDI diesel mechanic. San Mateo County CA would be best, but the wider SF area is OK.