Hello. I just picked up my TDI buyback replacement today which is an 07 530i. Love the car. Has comfort access that has worse range than anything I have ever seen. I searched the forums and saw lots of talk about the diversity antenna amplifier, but most of this people had FM reception problems. My FM reception is remarkable, but the comfort access is horrid. You have to be standing right next to the car to get the key buttons to work. Touching the door handles works maybe 1 out of 10 times. With the key in my pocket, the car will usually start, but half the time right after it starts it will give the key out of range signal.

Stopped on the drive home and replaced BOTH fob batteries. Any way to properly diagnose this without just throwing parts at it? Thanks.

 

not sure your problem is unique to the comfort access system or just generally related to the diversity antenna. i have an 07 E61 without CAS (my keyfobs have rechargeable batteries) and my remote range is pretty crappy. it works from ~10-20 feet from the car, but no further. I ordered a new key and the new one is no better. on my 2007 toyota, the remote range is 100 yards or better most of the time.

i'm curious to know what others have done or if the range on the E6x is just crappy.

 

I literally have to stand at the rear door to use the remote most times.

 

jesus that's bad. I'm assuming you bought it as-is and have no recourse at the dealer you bought it from?

 

Correct. Bought it from a used car lot. It's sitting in the garage tore apart for the satellite retrofit so I have time, just hate throwing parts at problems.

 

obviously, CAS-equipped models use some sort of trasmit/receive protocol to verify the proximity of the fob for the purposes of starting the ignition or opening the door with the button on the handle (RFID?).

however, i would guess that CAS and non-CAS models use a different protocol for general locking/unlocking and the panic button (and rear hatch release in the case of the E61). (RF?)

since you are having problems with both the CAS system (out of range error) and the general functionality of the fob (needing to stand right next to the rear window to unlock the car), the common denominator seems to be the diversity antenna.

 

I'm ordering a used one from eBay to try. I took mine out and it "looks" perfect, along with the fact that radio reception is perfect leads me to believe it's not completely dead, but maybe the CAS portion is.

 

FYI....I believe there is also a CAS control unit. I don't have the CAS system so I'm not familiar with how it's integrated into the car

 

Ok, thanks for the info. My money is on the diversity amplifier as the closer I get to it, the better it works. I see no corrosion or burnt marks on it, and as far as I can tell, the traces in the rear window look fine. If the used one doesn't fix it I may start experimenting with different antenna solutions.

 

Pelican Technical Article - BMW E60 - Remote Key Antenna Signal Booster