Did in fact something hit the car??? What loud noise did yu hear??
Did a bird or debris fly into the the open sunroof's track mechanism. Were yu driving highway or local slow speed?
Could be a fallen branch stuck in the sunroof track!
Not enough info. here.
The sunroof does have a failsafe to prevent caught hands from getting stuck. Just as the power windows have this feature. Is the loud bang directly related to the problem in your opinion?
Seems that something is jamming the track of the SR. that's why it opens 1/4 ways.
LT
