Quote:
Originally Posted by NoThanks
I have just one key fob and emergency key for my X5 and I just had my first experience with locking the key in the car. I am trying to learn more about the Comfort Access system and the ins/outs of replacement hard keys and key fobs.
There are reports on the forums that folks have 315mhz and 868mhz key fob transmitters. I'm guessing the difference has to do with those with keyless entry and those with comfort access, but I don't have any evidence to suggest that this is true.
When I decode my VIN I find the following option code:
S876A - Radio frequency 315 MHz
The back of my key fob is heavily worn and I can't clearly read the printed info...but I think I see 315 Mhz
The E70 comfort access training docs say otherwise: ID Transmitter
The ID transmitter for Comfort Access must be actuated by means of a radio signal. The ID transmitter is therefore equipped with a receiver for the coded 125 kHz radio signal that is transmitted by the outside door handle electronics module. The radio signal enables the ID transmitter to register with the vehicle (authentication).
For this purpose, the ID transmitter emits a coded 868 MHz high-frequency signal to enable identification of the ID transmitter as being valid and belonging to the vehicle.
The ID transmitter is exclusively responsible for use of Comfort Access.
The same document has no reference to 315 Mhz transmitters. My X5 is from the final month of E70 production and I'm wondering if maybe BMW was retooling from 868 to 315 as part of the F-series of X5s that rolled out later and maybe the transition happened well ahead of the F-series introduction, perhaps as part of the LCI Facelift in 2012?
Anyone have an input on why the transmitter frequency differences? Anyone have experience coding a comfort access key fob to a car without the dealer? |
If you use your VIN to look up the key diagram and part nbrs...if you look closely at the supplemental information in the part nbr index...it answers most of the questions you asked in regards to what frequency does your remote key operate on.
I used the VIN of a 2012 X5 35d (
L666318) to pull up a key diagram for an e70 X5...you can see in the text highlighted in the red box...that the part database explains which keys are 868 MHz and which are 315 MHz and which ones are 434 MHz...along with info about the various option codes.
The part database also reveals which of the two types of key sets that were offered during the e70 production run to use. When you search using your VIN, then the keys/key sets you use are highlighted (in this case #1, #2, & #7. The keys that do NOT work for the VIN I entered are "grayed out" and are NOT listed in the part nbr index below the diagram.
In regards to the transmitter info you posted...this is why buying keys from a non dealership can end up badly...there's a lot of things going on with the remote keys, central locking, EWS, and DWA (anti-theft alarm siren system) that have confused BMW owners for decades. And now that comfort access is tossed into the mix...there's even more stuff going on that confuses owners.
The comfort access
door handles send a 125 KHz radio frequency that is picked up by these new remotes...if the data communicated matches then this enables the door handles to be locked or unlocked by
TOUCH...without pressing any buttons on the remote.
Using the remote buttons to lock/unlock the car...that data is transmitted over the 315 MHz radio frequency to the aerial.
If you're going to purchased or replace a key and NOT use a dealer...then it is very important to know which set-up you have and what it will take to get all these independent systems to work together correctly. You need to know how it all operates as well as the person you're paying to make you a remote key.