my 2003 s430 is having a problem. i put the key in and it will not turn to start the car. also, the key fob battery is good but the car will not unlock every time but usually does after several tries. the key usually turns after repeated attempts but i can not get the key to turn anymore. any suggestions as to what the problem is? thanks for any help you may be able to give.

 

What about your second key? If it works fine, then your first fob has a problem.

For the fob you are using now, follow the instructions in your owners manual on changing the battery and re-synching it to the car.

 

did you get it resolved. I also have a S430 2003 model. No issues so far. I have 43000 miles on it. How many do you have?