My left turn signal was been flashing a lot faster than usual. Does anyone know why this happens and how to fix it? Is it indicative of a serious problem?

 

It sounds like you have a bulb burnt out on the left side, or if you recently replaced one it may not be installed corectly. Turn your signal on & inspect the car to see if all of your signals are flashing.

 

I had the same problem, mine turned out to be the parking light/turn signal socket in the front on the lower driver's side. $23 for the new socket and all is well. But it may just be a bulb. If the system detects a bad connection (blown bulb) it notifies you by flashing at a higher rate of speed.