We have a 2001 9-5 with keyless entry. Manual says it only works short range, and it does, and this seems to be intentional. Around 15-30 feet.
Today, while running errands, I was listening to CarTalk
Today, while leaving a church picnic, I was about 100 feet or more from the car, too far for the keyless entry to work. So, I tried it. It didn't work. I opened my mouth, stuck it in there and tried again.
The doors opened!
Charles