2008 4.8, key fob dead
 

as the title states, my key fob is completely dead. i have comfort access and have taken the key apart with a razor blade to check the internals and noticed nothing strange. the slot inside the car will detect the fob and I can start it without the key in the slot, but nothing else works.. I was told by an individual that it's a faulty antenna somewhere in the liftgate. anyone experience this?

does your second key work normally? or both keys have the same issue??

Only have one key..

Maybe the battery is dead?

See if this might help you, and I'd get a second FOB just in case..

https://www.youtube.com/watch?annota...&v=J2mM7woeTWQ
https://www.youtube.com/watch?annota...&v=J2mM7woeTWQ

Have tried several batteries

CA antenna is not in the lift gate .. it is located under the bumper ... easily accessed. See if it became unplugged, or if the wiring or something got damaged.

Each door handle has a built-in antenna too.You need a proper diagnostic equipment to make a proper diagnosis of the problem.

Please do not keep starting new threads when people dont reply...

http://www.xoutpost.com/bmw-sav-foru...lems-w-ca.html

you need another FOB.

This issue is NOT an easy 'check the fuse or wiggle the antenna' fix.

Why would you own a car and only have one key?!?!?

100% agree. it is not simple. read this, then take it to a qualified shop:

http://www.bmwmotorsports.org/pdf/e7...t%20Access.pdf

One of my fobs was submerged in water. Are you suggesting that I get rid of my car becuase I only have one key fob for it?

Yes, that is precisely what I am suggesting.

Who wants to bet OP is a phone-app user... cannot look at attachments, cannot search for the other 300 similar threads... hasnt reviewed the pdf....

When your fob was submerged, I would have decided "hey, lets replace that fob- maybe hit up xoutpost, bimmerfest, etc, etc, and find the cheapest way (ebay, reprogram, whatever) to replace it...because I dont want to be caught keyless if THIS one fails"...not an emergency, but get on it and have that second key in a few weeks.

Or, as you correctly point out, you could have sold the car.

;)

:rofl:, Dude, that would be rather extreme, I'd think picking up another key fob would be a better option, no way I would ever have a vehicle with only 1 way to open and start it, what happens if you lose it or it doesn't work?.

Harry

I just washed one of my fobs and if I leave the battery in it all the windows will roll down and the alarm will turn off. Thats pretty great when you live in the city and leave your golf clubs in the car all the time.

Update, i noticed something strange today while washing the car. I left the key fob next to the cup holder inside the vehicle with the doors closed and grabbed the handle and the car kept unlocking and locking while grabbing the handle. Seems like if I leave it in that area strange stuff happens. Also get a key not detected message, engine start not possible message at times. Is there an antenna behind the radio or something?

Perfectly normal ... you have comfort access (remote unlocking of doors). Same thing happens when you leave your keyfob in your pocket ... If you grab the door handle first near the touch pad on the handle and before you slip you fingers through the handle, it will attempt to lock and then immediately unlock.

I know, the problem is that the CA seems to have failed also and decided to randomly work that one time..