My 2007 Ford Five Hundred's Traction Control dash light (little car w/skid marks) comes on intermittently, stays on, the next time we start the car, it's off, then comes on after a short trip. It keeps doing this. Why and what happens if we don't do anything about it.

Assuming you don't live in the Automotive Abuse world,like most people. I would forget the dealer because of the price factor on labor and parts. You should have a good local repair shop, you use several times a year,even when you have no issues. You should expect to pay $70.00 to hook up a professional scanner,seeing as how they cost $10,000 and are a necessary item to work on todays vehicles. The wheel speed sensor is an input to your ABS Braking System. You'll have the dash light on until it is replaced or what ever else may be the problem. These is no real harm or danger, if that is your question. Expect to have different issues like this on your vehicle once a year. There very complex and difficult to troubleshoot and a little more expensive to repair due to the amount of time needed to find the issues. Assuming you don't live in the Automotive Abuse world,like most people. I would forget the dealer because of the price factor on labor and parts. You should have a good local repair shop, you use several times a year,even when you have no issues. You should expect to pay $70.00 to hook up a professional scanner,seeing as how they cost $10,000 and are a necessary item to work on todays vehicles. The wheel speed sensor is an input to your ABS Braking System. You'll have the dash light on until it is replaced or what ever else may be the problem. These is no real harm or danger, if that is your question. Expect to have different issues like this on your vehicle once a year. There very complex and difficult to troubleshoot and a little more expensive to repair due to the amount of time needed to find the issues.