[ryan stewart]

Central locking works using the physical key in the door and the button in dash but keyfobs stopped working altogether. Went from full comfort access to NOTHING immediately. It worked letting the dog in the back, closed the hatch and that was all she wrote, never worked since.

Ive searched and it appears its possible the modules under the rear bumper can fail. Before I pull the bumper off is there anything I should look for via code reading I can verify? If so then I can order the part ASAP and sort it out later.

[jsunma]

What you're referring to is the diversity antenna that's under the rear spoiler, not the bumper (absolutely I want to save you the trouble of pulling off the bumper! ).

Odds are that the real issue is a broken wire that powers the diversity antenna...although it's possible that it's the antenna itself, it's not likely. Likewise, it could be a fuse (check...that's simple), but that's unlikely as well. All of this is based on personal experience as well as lots of reading here.

If you're handy with a voltmeter, you should be able to test for voltage at the antenna module itself. Here's a link to the wiring diagram over on TIS - https://www.newtis.info/tisv2/a/en/e...te-key/uQsPxyh

Let me say that that's the one for MY car (a 2/2008 328i RWD/6MT). You may need to drill around on that site to find the proper diagram for your car.

If you find that there's no voltage, you'll need to open up the rubber wiring conduit (the one on the RIGHT side of the hatch as you have it open and face it) and look for the broken wire. It'll be in there. The easiest way to do that is to carefully slice through the rubber, spread apart the sections and look. And then once the repair is done, cable tie/tape it all back together.

There's a more professional repair possible involving a replacement wiring harness and a new conduit...but that costs a lot and takes a ton of effort. I originally had the slice and tape method done on my 2008 E91 at the dealer...and frankly, I'm happy as it's saved me time/effort/money each time I've had to re-do the job, which at 210K miles has been about 4 times. I'm now starting to replace the wire each time I go in with higher grade (than what BMW used originally) silicon-insulated wire (aka "RC Aircraft wire"). That seems to take the stresses of constantly flexing better, and I hope breaks less often.

Just comes with the E91 territory. (most wagons, frankly)

[ryan stewart]

Ok thanks. I'm going to bet money it's that wire issue then because I opened the hatch wirelessly, closed it and game over. Worked flawlessly until that point.

I just didn't realize it could effect the side doors too, thought it was just impacting the hatch function. I can't even press to lock/unlock anymore

[jsunma]

When the diversity module doesn't get power, you might as well be pushing the button on your TV remote. No one's home in the car's electrical system :-)

You may find that you don't have radio reception either. If that's the case, you might have TWO broken wires in that harness on the right side of the hatch.

Oh, and I'll add that when you have the spoiler off and are looking at the antenna (this will make more sense if you look at one of the threads that have pictures or just see it for yourself) you should check to make sure that no water is getting into the place where the antenna is. Some folks have experienced that and in those cases, it really IS the antenna module that goes bad. Some owners have used silicon caulking to seal everything up well. I myself haven't had the water problem, and I have lots of miles. But it's a good thing to check for once you're in there.

[slupie]

Originally Posted by ryan stewart

Central locking works using the physical key in the door and the button in dash but keyfobs stopped working altogether. Went from full comfort access to NOTHING immediately. It worked letting the dog in the back, closed the hatch and that was all she wrote, never worked since.

Ive searched and it appears its possible the modules under the rear bumper can fail. Before I pull the bumper off is there anything I should look for via code reading I can verify? If so then I can order the part ASAP and sort it out later.

Few posts that might be worth reading, based on my experience I vote for broken wires on the right side. Open the hatch and flex the rubber boot on the right side and keep pressing the remote buttons. If it all the sudden starts working it's broken wires. I have done this repair 3 or 4 times, currently I replaced the wires with igus high flex cable to see how it holds up. I think this is what i got from my supplier, https://www.igus.com/product/894 - 4 conductor, 18awg

https://www.e90post.com/forums/showthread.php?t=928522

https://www.e90post.com/forums/showt...t=broken+wires

https://www.e90post.com/forums/showt...t=broken+wires

[tlow98]

Yeah sounds like common broken wire issue for e91s...

[ryan stewart]

LOL, I didnt even have to get fancy with squeezing the boot. Hatch closed = system broken, hatch open = system works.

Seems like an odd design to have the system be so dependent on that antenna module, i though there were some in the doors too. Ive seen E91 hatch threads but I always thought it was about the latching/locking functions of the hatch itself.

[neilvan]

Same common issue as E61's. Check the hatch wiring first: Guaranteed some wires have the coating broken on a few and maybe even a few broken wires.

Beyond that check the diversity antenna; There might be some corrosion. Some isopropyl alcohol and a nylon brush(old tooth brush) should clean it up to work or maybe better than before)

[NYBulldog]

I did not have any issue with the Antenna (yet) BUT when I messed around with the shifter one time, I blew a fuse and nothing on my Fob would work.

[ryan stewart]

So its the wires. I removed the spoiler per this guys instructions:

The diversity antenna was pristine so I traced those wires back from the 4 prong plug. Pulliing the grommet from the body side I was able to liberate the red/black wire about 3 inches into the grommet, right where it bends the most.

I am NOT going to cut a grommet, hell no.

So i removed all of the friction tape from the plug end (on both ends before it reaches where the grommet passes through the window bracket). Then I used the 3 non-broken wires to "worm" the wire out the body side of the grommet. Where I would work my fingers up the wires from the body side to compress the grommet, then gently pull on the plug end of the grommet to slowly slide the wire down the grommet till the plug hit the grommet. THen I had plenty of space to work with.



I then cut the 3 remaining wires in the same spot. They were pretty beat up anyway, it looks like it "kinks" there instead of a smooth bend.



I have stranded wire so I just cut a few inches of wire and soldered and heat shrink to extend all 4 of them about 3 inches. That way I could go an inch or so past the kink in the grommet so my joints weren't being bent, only the new wire.



Then you just have to wiggle it back out just as before, but go an inch longer. Thankfully I had friction tape and whatnot to seal it back. You could just use electrical tape I guess. Then just make sure and tuck the little bit extra when putting the spoiler on so it doesnt get pinched.



Plug it all back up and good to go. The module looked good and the cover wasnt compromised. The only thing you see is the dirt from my hands touching it:



Then the only thing to keep an eye on when replacing the spoiler is you have to get these things to hook before you get the stud through the hole in the middle:

[ryan stewart]

If that gets me another 12 years then Id call it a success.

Thanks for the help guys.

[slupie]

Originally Posted by ryan stewart

If that gets me another 12 years then Id call it a success.

Thanks for the help guys.

Good job on the fix, but your photos aren't showing.

[ryan stewart]

Originally Posted by slupie

Good job on the fix, but your photos aren't showing.

Google treats everything as a confidential dick pic until you do the shared album dance. I updated the links and hopefully they should show now. It shows in an incognito window for me.

If this returns I have this strain relief stuff that kind of looks like a chinese finger trap (woven ballistic nylon) I can put over the bundle and slide up into the grommet to help provide a little rigidity and friction protection.

[tlow98]

Nice, I’m sure my 91 will need this one day. Appreciate the thorough documentation.

[krhodes1]

Does this happen more from time or usage? My e91 only has 47k on it, and commensurately little use of the hatch.

She's semi-retired, gets ~2K put on a year now, lives at my summer place in Maine.

[ryan stewart]

Going to guess hatch usage is the culprit. Im in and out of mine constantly so I wouldnt be shocked if mine came early.

When I opened it you could clearly see a kinking of the wires and wear on all 4 wires in the same spot. I suspect Ill probably see issues with the latches or wipers and whatnot eventually.

Or even a leak in the rear window sprayer.

[ryan stewart]

Originally Posted by ryan stewart

If that gets me another 12 years then Id call it a success.

Thanks for the help guys.

Well, I didnt get another 12 years but at least I know whats going on. This time it was intermittent, I could pinch/wiggle the boot and it would work for a bit. Popped it open and the wires hadnt completely broken like before but I suspect were broken inside the jacket.

I just used some wire off my shelf the previous time but this time I went and bought some silicone jacketed long-life flex wire to hopefully finish it for good. I also got a bunch of colors to match the dominant color on the wires coming out of the car because this time what I did was solder a long joint, heat shrink, and then tuck all of the original wiring back inside the car. It felt stiff and brittle so I figured I would never touch it again if I needed a repair, just keep splicing into this new stuff. And like before I made it so there are two solder joints, one one each side of the bend with the flexible wire in the bend.

Additionally I popped open the drivers side, where the big power plug, brake light wiring and coax antenna come through. the wires were in pretty good shape I guess since its more of a twisting there BUT the jacketing on the fat, what I asssume are power, wires was splitting right in the middle. So I put a little liquid tape in the cracks and wrapped it all in super33.

Guess if it fails again I might look into that repair harness you can buy and just replace the whole boot too. The rubber on the boots has hardened and is probably contributing to causing a pinch point.

Edit: also just a tip, get some KY silicone gel and throw a dab on the wire before trying to pull it through the boot. Makes it a hell of a lot easier.