[uksteves]

Hello,

First post - hope this is the right sub-forum.

2005 E91 325i - been on vacation for a few weeks, and first time I used the car, the start process was a bit laboured/slow. Guessing this might be because it had been left standing for two or three weeks unused, I decided to put the battery on charge overnight (connecting a CTEK charger to the terminals in the engine compartment, which I've done a few times in the past with no issues).

Last thing I did before leaving the car was to lock it as normal using the key fob (i.e. remotely).

Went out this morning to disconnect the battery charger cables, and found the car had stopped responding to the remote keyfob completely. I feared the car battery had died, but on using the key blade to open the lock, the car came to life and the alarm sounded as soon as I opened the door. Putting the keyfob in to the slot in the dash stopped that, and I then tried to start the engine - no problem at all.

But I'm left with no remote unlocking access to the car. I have tried both keys, with no luck. Both keys worked fine up until yesterday - never even the hint of a problem.

The central locking system itself works fine (using the key blade, or the button on the dashboard - all doors lock/unlock as normal).

So I'm a bit stuck with what to try next. Have tried checking a few fuses - all of which appear fine. I've also tried disconnecting the battery to see if that resets anything.

I understand the antenna diversity module can fail due to water ingress, but the radio still has perfect FM reception (I believe the two are linked?) - and as I say, it was working perfectly until this morning - seems a bit of a coincidence?

Any thoughts? It's an 11 year old car, so I don't really want to take it to a dealer to diagnose the fault. I have access to an ODB cable and INPA (although I've not used it on an E90 before), is this likely to be any help?

Is there a process for resyncing the keys for remote locking? I thought there might be, but on reading it seems that providing they start the car, then they're OK?

Second question - whilst I'm sorting this out and being forced to access the car using the key blade, is there any way to disable the factory alarm system so it doesn't sound every time I open the driver's door - it must be upsetting my neighbours :-)

Thank you,

Steve.

[somedude81]

Hi Steve, I had the same problem and symptoms as you recently. After much experimentation, the problem did wind up being a blown fuse. There is a well documented problem with the door lock actuators blowing fuses. Those were fine in my car. The diversity antenna amp also has its own fuse (a pink 5A fuse), which was blown. On my car (a 2008) it was #63. After replacing it, remote locking was fixed instantly.

[uksteves]

Thanks for the hint.

I've just been out, and on my car fuse #63 is a 30 amp (I think its to protect central locking itself, because with it pulled, the central locking stopped working).

The only only 5 amp fuse on my fuse card which seems to be related to locking (on the card, it has a picture of a door with a key/lock on it) is fuse #2. I've swapped that with the CD changer fuse (also 5 amp), and no difference :-(

Anyone have any idea which fuse might protect the antenna diversity amplifier on a 2005 model? Interestingly, FM radio reception is unaffected, which perhaps means the module is still getting power?

[NightStalker]

Originally Posted by somedude81

Hi Steve, I had the same problem and symptoms as you recently. After much experimentation, the problem did wind up being a blown fuse. There is a well documented problem with the door lock actuators blowing fuses. Those were fine in my car. The diversity antenna amp also has its own fuse (a pink 5A fuse), which was blown. On my car (a 2008) it was #63. After replacing it, remote locking was fixed instantly.

Thank you. I was very close to replacing modules in my car which would of cost me $1,000 +

Checked 63 and boom back on track.

[jsunma]

Originally Posted by uksteves

Thanks for the hint.

I've just been out, and on my car fuse #63 is a 30 amp (I think its to protect central locking itself, because with it pulled, the central locking stopped working).

The only only 5 amp fuse on my fuse card which seems to be related to locking (on the card, it has a picture of a door with a key/lock on it) is fuse #2. I've swapped that with the CD changer fuse (also 5 amp), and no difference :-(

Anyone have any idea which fuse might protect the antenna diversity amplifier on a 2005 model? Interestingly, FM radio reception is unaffected, which perhaps means the module is still getting power?

Steve:

I'm not sure if your original question/problem has been resolved by finding a blown fuse, but if NOT, then you might want to look at the wiring in the rear hatch. Specifically, the wiring that runs through the rubber tube that goes between the body and the hatch.

I've had this same problem twice in my car (E91, 328i, 2008). I wish it was a fuse...I checked all of the fuses and found nothing blown. The first time I had this problem, I even replaced the diversity module to no avail. Ultimately, I took the car into the dealer for diagnosis and they found that several of the wires inside the tube had broken, causing the problem. The fix is simple and cheap once you figure it out. Unfortunately, the wires broke again...but at least that time I was able to find the broken wires myself and repair them. I'm fully prepared to have to fix this again at some point.

Google "E91 rear gate wiring" and go to the link on a UK forum for a full thread on the problem (including links to the various wiring diagrams that will guide your troubleshooting). This seems to be a common wagon problem, but there's not that much attention to it in the US forums due to the rarity of wagons. Folks over on your side of the pond seem to have more experience with this.

The wires that break are the ones that carry current from the diversity antenna to the connection to the footwell module (I believe). So, your remotes are sending a signal to the antenna but the antenna isn't able to send the proper signal to the car. This problem may or may not be accompanied by bad radio reception (depending on whether the wires between the antenna amp and the radio are also broken).

Good luck, and pm me if you have other questions.