My 2010 Jetta has been having some issues. Sometimes it’s hard to start- will take 2-3 tries before it starts up. Is this because it’s a diesel and needs to be primed before actually starting it up? The other day I had to jump it and it started just fine. I had battery/ alternator/ starter checked at auto zone and they said those are good. But 3 codes did come up when check engine light was on ( goes on and off). Now car is stuck at boyfriend’s work. He says he turned the car on and it started at first then the coolant light came on and when he tried to turn it back on he couldn’t.