I am periodically having problems with the key system not detecting my key, and therefore, not allowing me to lock the car using the lock button on the remote. Here is what happens. I put the car in park and push the button to turn the car off. I get out of the car and close the door. When I push the lock button, there is a long steady tone. I open the door and get back in, and the display is showing key not detected. In this instance, I had the key with me and in fact it I was holding it in my hand. This situation actually happened when my car was in for service at the dealer, but it seems that my dealer has only one person who has knowledge of the smart key system and that person just happened to not be there. This is not the first time where the key system can't detect the key. Any ideas on what is going on?

Assuming the system itself has no malfunctions, the most likely reason is signal interference. The only time this has happened to me is when I had my keys in the same pocket as my cell phone. I'm in the habit of making sure my keys are in a separate pocket then my phone. Others have reported instances of signal interference depending on location (nearby radio towers, etc.).

Maybe another reason is low battery in the key. Not sure how low the battery has to get before it triggers the warning on the dash, but perhaps its just low enough to cause occasional issues but no warning. Experiment by positioning the key closer and closer to the handle. If that still doesn't work, move to the passenger side and see if it works fine on that side. If it does, maybe the antenna in the driver's door handle has a loose connection and opening and closing the door closes the loose connection.

Two climate control systems, one inside and the other at the tailpipe.

Distance: 29169km (75% city - 20 min trips)
FE: 6.77L/100km or 34.7 mpg
Operating Cost: $0.066/km / $0.107/mile

According the the book that can actually damage the key. Permanently.