it can cause issues if the sonar sensors think you're going to hit something and put on the breaks. only the advanced model has them. It all depends on what kind of car wash. The ones that move around you or the ones that pull you through. all you have to do is turn off ICS and parking assist while going through.
I’ve taken my Advanced through the tunnel car wash several times. I try to remember to turn off the forward collision thingy, but the two times I’ve forgotten nothing bad has happened. I do get beeping and warnings on the MID, but the car didn’t stop.