Lost the key, how to start it without the chipped key?

You can't, you must have the key, or the security system will kick on. You will need to get an ignition lock and key from the dealer and have them code it for you. Or have a locksmith come out and do it for you which will run about $250.00. Here is how to replace the key tumbler to help fix the problem. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.