One problem related to speed sensor has been reported for the 1999 Chrysler Concorde. The most recently reported issues are listed below.
I have had my 1999 Chrysler Concorde lxi for about a year and a half. It now has 76,000 miles on it. I was pulling out of the parking lot and first noticed the speedometer wasn't working. At that point I kept driving. As I pulled out onto the road and had to accelerate I noticed my rpm's were a little high. The car seemed to be stuck in low gear. I checked the transmission fluid and the fuse for the transmission controller. Both were fine. I had the car towed. I got online and starting researching the car. It turns out that speed sensors in this car fail quite often. I spoke to the previous owner of the vehicle. He told me he already had the speed sensor replaced once just before I bought the car from him. My car is five years old, has 76,000 miles on it, and has had the same part replaced twice already. This is ridiculous. Chrysler should pay to fix their faulty product, not me repeatedly.