Key FOB issue

Since it's winter here in Ohio, I warm my SR5 up before taking off. I don't have auto start, so I lock the doors with my spare key while the truck warms up. For some reason, my spare key quit working while my truck is running. However, the spare key will lock/unlock the doors when the truck is not running. The spare key does not need a new battery. I believe I need to do a reset of some kind, but am not sure where to start. Any suggestions?

 

Are you saying that your REMOTE will not open the door when the motor is running?... Then use the KEY..!! Does the remote work otherwise..??

 

I do the same thing but I had just a blank key made to unlock the door. Had it made at the dealership service dept.

 

it only works when the engine is not running. I'll try switching out the remotes. If that doesn't work I'll lock on the inside and open with the key until I read the manual. It did occur to me to use the key to unlock, just hoping the remote would work like it did before. Thanks!!!