Just before a cross country move six months ago, a check engine light popped up with a code P0456 on my Jetta. My mechanic said the car is safe to drive and reset the code as I did not have any time to evaluate and fix the issue. The code came back on quickly, but indeed there has been no issue with starting or driving the car. Finally took the car to the new mechanic who said it's the faulty leak detection pump. The least I was quoted to replace is was about $450. Someone who used to have a 2005 Jetta said they had the same issue and that the mechanic told them this happens a lot on Jettas. Not a huge deal, but annoying.