E90 3 series - remote unlock/lock stopped working

[stevesuk]

Hi all,

Just got back from 2 weeks holiday, and our 2005 E91 (which was left on the driveway) was a bit sluggish to start - so I left it on a battery charger overnight.

Last thing I did before I left it for the night was to lock it (using the remote key fob).

Went out this morning to disconnect the charger, and both keyfobs won't unlock the car.

I can use the emergency key to unlock the car. Once I've done this, if I put the key in the slot on the dash everything works perfectly.

So I doubt its the key fobs (both worked fine yesterday) - I guess the process of charging the car battery has upset something?

Any ideas how to diagnose/start looking? I have INPA available.

Might disconnecting the battery (the car battery) help to reset something?

Oh. and in the meantime, is there something I can do to stop the alarm sounding every time I open the door using the emergency key?

Thanks,

Steve.

[Ciaran]

Would the central locking fuse have blown, happened to me once or twice over the years.

[stevesuk]

Ciaran said:

Would the central locking fuse have blown, happened to me once or twice over the years.

Central locking works, but only using the emergency key blade (i.e. when I turn the key in the lock, all the doors unlock).

I read that the antenna diversity module (which is in the tailgate) can fail due to water ingress, but it sounds like a bit of a coincidence that it was working 100% fine yesterday, but not this morning. I didn't even open the boot to charge the battery (used the connections under the bonnet).

I've done this (using a CTEK charger) a few times over the past few years, and never had a problem.

I think I'll try disconnecting the battery tonight to see if that sorts it out.

I wouldn't be that bothered about having to use the key to open the door, but I'm more bothered about it setting off the alarm each time

[bubilas]

stevesuk said:

Central locking works, but only using the emergency key blade (i.e. when I turn the key in the lock, all the doors unlock).

I read that the antenna diversity module (which is in the tailgate) can fail due to water ingress, but it sounds like a bit of a coincidence that it was working 100% fine yesterday, but not this morning. I didn't even open the boot to charge the battery (used the connections under the bonnet).

I've done this (using a CTEK charger) a few times over the past few years, and never had a problem.

I think I'll try disconnecting the battery tonight to see if that sorts it out.

I wouldn't be that bothered about having to use the key to open the door, but I'm more bothered about it setting off the alarm each time

Hi Steve,

I have the same problem with my e91. Both key fobs decided not to function at the same time. Central locking works fine with emergency key blade. What was the problem in your case?

Thanks

[stevesuk]

bubilas said:

Hi Steve,

I have the same problem with my e91. Both key fobs decided not to function at the same time. Central locking works fine with emergency key blade. What was the problem in your case?

Thanks

Hello there - it was the antenna diversity module (sits underneath the spoiler on the tailgate) that had stopped working. Think it cost us about £350 to get it replaced by our local independent - all good ever since. Apparently they usually fail through water ingress, but ours looked to be sealed OK. Apparently on close inspection, there were some hairline cracks on the circuit board.

There are some fuses you can check too (although ours were fine).

[TinaHoro]

Hi Stevesuk

I am having same problem with my E90 320i facelift. But the issue that annoys me is off the alarm that goes off when you unlock the doors using the steel key. Well since the remote is not working, how do you turn off the alarm ?. I havent opened the car since the remote wont work and im hesitant of the annoying alarm which goes off when i open manually.

[RUSSELLM]

To lock the car, are you using the blade or the fob ?

[TinaHoro]

The last time i used the car, i locked it with remote. Opened and closed with remote no problem but the next day when i tried the remote, there was no response from the car. The blade works but everytime i tried to unlock the doors in past times with the blade, the alarm goes off immediately. So this time im afraid since the remote doesnt work, the alarm might not stop sounding

[RUSSELLM]

When you open the car with the blade, and the alarm goes off, how do you silence it ?

[2 GKC]

Put the key in the dash. That turns the alarm off
Take the fuse out for the alarm. When I open mine now just the hazards go.
Can’t bring myself to spend the money to get it fixed

[RUSSELLM]

If you lock the car with the blade, does that arm the alarm ?

[2 GKC]

Yes

[stevesuk]

2 GKC said:

Put the key in the dash. That turns the alarm off

Yep, that worked for me when ours was playing up.

Just a couple of annoying seconds listening to the alarm each time I got in to the car - I managed to get the swift insertion of the key down to a fine art before it was fixed.

From memory, ours cost about £350 - but I didn't mind paying it. It's a good time to be running an older car. I'd hate to be leasing something new at the moment - looking out of my lockdown window and seeing it sat there on the driveway costing me £300 a month.

[TinaHoro]

Which fusebox and fuse is for the alarm ?.

[2 GKC]

Fuse box in the glove box. There’s a guide in there I believe

[Brian Cuthbert]

Thanks to this thread, I was able to direct the auto electrician to the cause of the fault, and where the unit is located in my 2010 E91. Dry solder joint in the antenna diversity module. It was an intermittent fault but I have some confidence it’s fixed!

[g3org3y]

Brian Cuthbert said:

Thanks to this thread, I was able to direct the auto electrician to the cause of the fault, and where the unit is located in my 2010 E91. Dry solder joint in the antenna diversity module. It was an intermittent fault but I have some confidence it’s fixed!

Hurrah. PH delivers again.