Submitted by mike_f on 02. April 2016
Woke up this morning to find that my MX would not respond to either key fob. I had to use the mobile app to unlock the car and start. Called service and was told that batteries for BOTH key fobs had to be replaced? Something about a known problem with the key fobs. Sounded a bit off that both would go kaput at about the same time. Took my MS over to the SC and they replaced both batteries (they actually wanted me to drive the MX over using my mobile app..LOL...they seemed to think it was something with the car). Got home and Voila, the car worked perfectly. My guess is what is happening is that unless the key fob is out of range, it is still in communication with the MX (this was the problem with the driver side door opening and closing, it was in contact with both key fobs even though the second was in another room) causing battery drain. I suggest that when parked, both key fobs be located as far from the MX as possible or placed in a metal box (Faraday cage) to eliminate the RF link.