In all 13 years had no light.. suddenly it's on. I took it to the local Benz dealer and it was the temp sensor in the air-intake duct. $12.90 and $94 for diagnostics! Here's the problem, the dealer didn't have the part in stock and when it came in I drove there to buy it, they wanted $28.50 to install it. I KNOW EXACTLY what part it is and where it goes. In 30 SECONDS I had it installed while I was waiting in line for an apointment. I asked if they would reset the light (codes) and they told me it would be another $94 (min hour) fee!!! How can I reset the codes or otherwise make the light go out? Oh, I didn't tell them I put the part in and I was very nice to them. I was under the impression that if I paid for an hour (originally) and the installation ($28.50) was WAY over charging that atleast it would only cost $28.50 to reset the codes. It's not my fault they didn't have the part!.. I'm sure you didn't need all that info but I thought others should know. Just because 'we' worked hard and earned one of these cars gives no one the right to rob us.