My 2008 Miata with Advanced Keyless Entry stystem shows a "KEY" warning in red letters sometimes. The manual warns that cell phones could cause this or maybe the key card needs a battery. I've put in a new battery. I don't turn on my cell phone. I've taken it to my Mazda dealer who has put in a computer module card, twice now. And, I still get the warning occasionally. Anyone know what's going on?