2009 3.0 xf

[Daz joyce]

hi all would anyone be able to give me some advice, as i am going crackers

were do i start, a while ago, the we went for a meal, the car was great, we came out, it was completely dead, nothing , ie nothing, went to the battery , wiggled the battery cable, everything back on, and started, got home, fine for a week, 

then completely dead again, did the same thing, all came back on, took the car to Jaguar, and they said it was the negative lead playing up, so had it replaced and car was all good for a month, yesterday wife calls me, saying both our fobs have failed and she cant get in the car, i replaced both batteries ,still nothing, used emergency key, car completely dead again, call RAC. they put there jump leads on car, and it started to drain his battery, so he disconnected it, on his computer the battery said 1 volt, this is a brand new 900ah uassa , he thought it was the alternator that had gone, and done battery, we were both just looking in the boot, when all of a sudden the car locked its self, he put this jump leads back on, and the car started instantly . we gave it 10 minutes, he put his test equipment back on, tested the alternator perfect, it had started to recharge my battery,  we checked for battery drain when turning the car off, 0.02 ,so nothing, so he had done his job and got car started, i turned it off, left it for 2 hours .went back out and it started instantly. so from a new battery with 1 volt showing to a battery showing 14.76 volts and a starting car within 3 hours.

 

so i have no battery drain, i have a good battery, i have a good alternator, the fobs are working now, and i have done nothing, what is going on, as an electrician its doing my head in, i have noticed there is a small connector plugged into the 

negative lead, its this the bms , if so, if there is a intermittent break in the cable, could this drain the battery to nothing, and when contact is remade work again, no fault lights on dash, no fault codes    any advice on my problem 

[Bonzo123]

I have recently had the same problem. I have two fobs. The most used fob I was using started to play up. Like you I replaced the battery. Managed to enter & start the car no problem. I left my car for about ten days, then I needed it & the fob wouldn’t work. I looked online & found how to remove it cover on the NSF door. Slid rearward, then I pulled the key and opened the n/s door & the alarm started then I wondered if I put the key in the dash it stopped. Car would start & drive. Looking again online again, I found you might need your fob recoaded with a code reader. I haven’t got one either. So I can still use the other fob without any problems. I hope this helps you out. Good luck m8. Dez