Hi can anyone assist on this. I have replaced the batteries on both fobs and can drive the car (ie it does start - so the fob does talk to the car, though I recently had to try several times to get the car to start) but now cannot lock the doors using the fob. The problem has been getting worse... at one point the lock was working on the third or 4th attempt, holding the lock (or unlock) button down hard. I think I replaced the battery on that fob after that. Someone mentioned when you change the fob battery you might have to re-set something eg use tools on the screen etc, but I never did that before when replacing batteries in the fob and all was fine. Mind you I would have expected longer life from those fob batteries as on my last car I never had to do it. I have used reputable battery brands.

BTW I did see this
To program an 850 FOB, turn the key in the ignition on and off five times fairly fast. On the last time leave the ignition on at which time you should see the red LED on top of the dash flashing. While it is flashing, press the button on the FOB. The rede LED should acknowledge the programming. If you have more than one FOB, these must be programmed as well and within 10 or 12 seconds of each other. Then switch off ignition, and check that FOBs work.