This seems to be a defect with these cars, I've had the same issue 3 different times. Replaced the crankshaft sensor and that fixed the problem, but the fix lasts from 2 to 4 years before I have to replace it again.

removing the small timing belt

My car engine went suddenly off. took it to the Mechanic who found out that the small timing belt was torn and hit the crank shaft position sensor. The sensor was replace, but the small timing belt was not replaced as per the Mechanic not required .He said it will cause more trouble to the car that benefit. I argued with him but he insisted not to replace it .I am requesting your kind advise in this matter . Please reply soon what to do.