Remote keys only work with tailgate open after disconnecting/reconnecting battery
 

Hello all. I did a bunch of googling on this issue to no avail. Sorry for the long story but I don't know what may or may not be relevant.


I recently purchased a 2010 E61 (N54) w/ ~70K miles. I was getting a 'low battery' message when using the radio in the car for a couple of minutes after turning the car off. Auto parts store tested the battery and it read 550 CCA. Car has a BMW battery that's just under 2 years old rated at 850 CCA, AGM I believe. I took it to the dealer, hoping the battery would be the problem and it would still be under warranty. They diagnosed the problem as a faulty IBS and said everything else tested OK.


This weekend I disconnected the negative terminal so I could take a look at the cable/IBS to see what I'd be dealing with and make sure I order the correct parts. Since reconnecting the battery, both remote keys function intermittently. It seems the only time I have been able to get them to work is if the tailgate is in the open position and locking/unlocking work fine. As soon as I closed the tailgate all remote key functions no longer worked. However as I said it is intermittent and I think when I last tried I couldn't get the remote keys to work at all irrespective of the tailgate position.


Current status: I'm waiting on parts to do the IBS replacement and using the physical key in the door. I am getting a "increased battery discharge" message that I was not getting before I started tinkering. I disconnected the IBS data cable for the time being to see if it affected anything and thus far it has not.


Any ideas what could be causing my remote keys to no longer work reliably?


Thanks!

Looks like I didn't search hard enough because as you've said this issue is very common. It is quite a coincidence that it happened at the very moment I disconnected the battery, but that appears likely. I will check my wiring and report back. I did notice this morning my defroster does not seem to be working either. Thanks for the response kd7iwp!

Just wanted to close the loop on this thread -- the problem was the tailgate wiring. Right hinge, left bracket, there was one severed wire and a few were chewed up a bit. The 14 AWG wire was hanging on by a thread. Spliced in some new wire and used solder butt connectors and everything's working great since, knock on wood.

So glad to hear you found the problem! I’m tempted to order the Sencom rebuild kit but none of my wires are currently broken and I have enough other projects to take on at the moment.

Do you know the best way to order the Sencom kit? I read something about import duties and customs which sounds troublesome.

Although my car's good at the moment, I just peeked at the tailgate wires again with the flashlight and I think I saw a broken wire I hadn't noticed before and the wire wrap/tape coming off in some areas. I think it's just a matter of time before it all needs to be redone.

Brian

2008 535xi wagon

I am having Comfort access key issues and have to use the actual key in the key hole.
1. had all the wires going through hatch redone and redone to check again.
2.replaced the car battery - new when I acquired the car 5 years ago
3.replaced the key battery
4.checked diversity antenna (in the spoiler) - some corrosion was found, tried to clean, ended up buying a new used one without any change..
5.clicking noise behind the glove compartment when turn the car off. Not sure what that is about, help
6.checked fuses in rear, fine
7.no water damage visible around diversity antenna.
8.replaced voltage regulator on alternator as I was getting 15.8 volts, now 14.7, is that still to high?
9.interior buttons work, fm and am radio good reception
10. Defrost and tail light did not work before rewire, all functions work

Remote to start car works only if I start the car, stop, pull key out and keep it within an inch of the slot and then only then can I only start the car. Unlock and lock does not work.....

Resources:
https://www.autogenius.info/18881/ fuse layout

thanks in advance for any help

My comfort access was barely working when I bought my E61 last year. To start the car I always had to hold the key behind my right shoulder and the lock/unlock buttons on the fob only worked if I was holding the remote about 2 feet from the rear window. My antenna amplifier looked just fine and was labeled 2015 so it must have been replaced by someone. My radio reception was pretty awful. I got a used antenna amplifier on eBay and it solved my problem. Considering how often these fail, I'm voting that you got a bad used one... I grew up in Renton and now live 2.5 hours north of you. Next time I'm down there I'd be happy to swap my amplifier into yours and see if that solves the problem.

Hello kd7iwp, Thanks for the offer I would like to find out. I did buy the eBay insurance on the device. PM me when you are thinking of coming down, or I could drive up your way if you are available some weekend.