Happy to find after several months and $400 + dollars my lost engine key and FOB.....EXCEPT, the key will light up the dashboard and accesories but will not start the engine???? The FOB will do nothing.....I programmed my other two key FOBs and they work fine. (I did replace the battery).....
Any thoughts appreciated!!!!!

 

Ok, you replaced the battery. Did you clean the contacts?

I find that a cotton swab and some isopropyl alcohol works. Just make sure not to drown the fob in the solution. Remove any black gunk from the contacts. It's residue of the melting rubber buttons.

If that doesn't work, check to see if there is any signal being output from the fob after you clean the contacts. This would be easier if it were an IR signal, you could press on the fob while looking at it through any camera. However, because these are not IR fobs, you could take it to Pep Boys, et al. They usually have a signal scanner at the cashier. Press button on scanner, point and click. The scanner should light up if the fob is working.

I suggest you try cleaning the contacts before the scan. If they are dirty, the scanner might not pick up on the signal because none is being emitted.

 

The key may have to be reintroduced to the computer.

 

Perhaps the little transponder in the key head took a hike or broke? I had a key that quit working and I discovered an empty dark hole in the back of the key, no idea where the transponder went.

 

If you had a new key programmed the old one will be toast until it is also reprogrammed.

 

Why is that? Wouldn't that become an endless loop of reprogramming fobs?