One problem related to brake drum wheel cylinder has been reported for the 2012 Volkswagen Jetta. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Volkswagen Jetta based on all problems reported for the 2012 Jetta.
While driving at any unknown moment the car will start to misfire in 1 or more cylinders (seems like usually when there is moisture in the air) but you still never know when it will happen. This causes the vehicle to suddenly go into engine power control and will sometimes cut off the steering and brakes. I've gotten caught in the middle of an intersection with no brakes and no steering. I had to use my parking brake and shut the engine off. Most of the time the steering goes out is when I'm trying to make a u turn. And most of the time the engine starts to misfire and/or shut off is when I'm trying accelerate either after being stopped at a red light or significant increase like merging on a freeway.