P0385 Crank Sensor ????

My 99 STS SES light came on with a P0385 crank sensor circut B malfunction.
The car has stalled recently at a stop & does have a slight rough idle. Does anyone have experience with this problem or changing this sensor. I was wondering if it is located on the harmonic balancer or back on the flywheel/bellhousing area. After clearing code it does come back immediately.Any help or advice would be appreciated.

Hello, I am no expert, but most cars I have delt with the sensor was always on the harmonic balancer and the pick- up sensor next to it. More than likely the pick-up has a intermittent problem , or maybe there is more than one pick-up? I worked on a 1300 Kawasaki 6cyl. that had 3 pick-ups one for every 2 cylinders. I was cutting out every now and then. One was the problem.