Oh No , Not Again !!!!!! z3 2.8 2000

[cooknerkid]

I thought i had fixed it, but 2 weeks after sorting the cable tie around the anti-theft radio sensor, my alarm has gone off twice .I have now replaced bonnet switch , checked boot sensor for damp etc-none found. After doing the radio sensor, the arming lights between the seats do not now flash violently for 30 seconds and then settle down as they did before. A mate suggested it may be control unit in front of the gearstick under the console, but I believe they are approx £100, its an expensive guess!!!! It goes off totally random- 5 times in a day then nothing for 3 weeks--Any ideas as it is driving me mad !

[Robert T]

There are only a limited number of possibilities. You have the later alarm, so if you get really stuck, they can be plugged in to read which sensor triggered them.

First, discount the interior movement sensors by turning them off when you arm the alarm - do this by pressing the lock button a second time within 10 secs or so of locking the car. If it still goes off, it's not them!

Other things to check:

1) Does you interior light come on randomly? (make sure it isn't switched off first!). If so then the button on one of the door strikers is probably worn and this is also used for the alarm. They can be fixed by gluing a piece to the worn part so that it depresses fully.

2) Is there water in the left hand (UK passenger) boot well? If there is, then the tilt sensor is in there and it could be that.

3) Do you have problems with your boot lock? You could have an intermittent connection in the boot lid wiring, and as the boot switch goes through there, that could also trigger the alarm.

4) Although you've changed the bonnet switch, it could still be that, so try disconnecting it.

That's all I can think of right now.

Cheers R.

[cooknerkid]

There are only a limited number of possibilities. You have the later alarm, so if you get really stuck, they can be plugged in to read which sensor triggered them.

First, discount the interior movement sensors by turning them off when you arm the alarm - do this by pressing the lock button a second time within 10 secs or so of locking the car. If it still goes off, it's not them!

Other things to check:

1) Does you interior light come on randomly? (make sure it isn't switched off first!). If so then the button on one of the door strikers is probably worn and this is also used for the alarm. They can be fixed by gluing a piece to the worn part so that it depresses fully.

2) Is there water in the left hand (UK passenger) boot well? If there is, then the tilt sensor is in there and it could be that.

3) Do you have problems with your boot lock? You could have an intermittent connection in the boot lid wiring, and as the boot switch goes through there, that could also trigger the alarm.

4) Although you've changed the bonnet switch, it could still be that, so try disconnecting it.

That's all I can think of right now.

Cheers R.

Thanks- not noticed the interior light- Took car to local Indy who said there were no faults listed on Alarm- Even though that was before I did the radio sensor-- I was under the impression that if the 'Armed ' light flashes violently there was a sensor fault-- I will try the double lock to see if it is the interior sensors,, Thanks again

[Robert T]

The alarm is not a fault code. There is a register of how many times each sensor (well, sensor input, as some are combined) has triggered the alarm. This can be read with the appropriate software. BMW checked mine for me and I have a print out. You probably need to clear the registers first, as mine showed when I accidentally triggered the alarm by opening the boot with the key.

Cheers R.

[cooknerkid]

The alarm is not a fault code. There is a register of how many times each sensor (well, sensor input, as some are combined) has triggered the alarm. This can be read with the appropriate software. BMW checked mine for me and I have a print out. You probably need to clear the registers first, as mine showed when I accidentally triggered the alarm by opening the boot with the key.

Cheers R.

Thanks again Robert, I feel it will need a clearout first- the alarm has gone off randomly for the last 12 months now- As I dont have an owners manual I was unaware of the double clicking procedure--- I have now locked car and double clicked -- we will see how we get on -- When you had yours checked -what was the fault ???

[Robert T]

Mine was a weird one. It turned out to be the interior movement sensor. I had been footling round in the dash fitting a new stereo and it seems that a label detached itself near the movement sensor - the slightest air current would probably cause enough movement to trigger the alarm - I found the label sticking out the side of the centre console a short time later and since removing it the alarm has behaved itself! I also cable-tied the stereo switch whilst trying to sort this and noted that the alarm LED now behaved as it should.

If you have access to something that can read the codes, it can help, but you can do it by trial and error just as well.

Cheers R.

[cooknerkid]

Mine was a weird one. It turned out to be the interior movement sensor. I had been footling round in the dash fitting a new stereo and it seems that a label detached itself near the movement sensor - the slightest air current would probably cause enough movement to trigger the alarm - I found the label sticking out the side of the centre console a short time later and since removing it the alarm has behaved itself! I also cable-tied the stereo switch whilst trying to sort this and noted that the alarm LED now behaved as it should.

If you have access to something that can read the codes, it can help, but you can do it by trial and error just as well.

Cheers R.

where exactly is the internal sensor then- I read they were in the footwell , but havent seen it ????

[Robert T]

The movement sensor is inside the centre console, on top of the propshaft tunnel (technically the gearbox tunnel, but you know what I mean). I became acquainted with it, or at least my knuckle did, when changing the heater control bulbs.

Cheers R.

[cooknerkid]

The movement sensor is inside the centre console, on top of the propshaft tunnel (technically the gearbox tunnel, but you know what I mean). I became acquainted with it, or at least my knuckle did, when changing the heater control bulbs.

Cheers R.

Thanks very much -- I will try all the permutations you have given me, cheers Cooknerkid

[PCSAM]

if all that fails i have a few control units . i purchased them as a bulk lot but in the end the wiring loom to the alarm on my car was a mess ( no alarm for me ...) but i do still have the control units (4 of them and key-fobs)

[Zed Carer]

The movement sensor is inside the centre console, on top of the propshaft tunnel (technically the gearbox tunnel, but you know what I mean). I became acquainted with it, or at least my knuckle did, when changing the heater control bulbs.

Cheers R.

The movement sensor on my 99 facelift 2.8 is fixed to the back of the under dash trim panel above the pedals. It was the one connection that just wouldn't gome apart when I was taking the dash out. It's visible in this picture.

[Robert T]

The movement sensor on my 99 facelift 2.8 is fixed to the back of the under dash trim panel above the pedals. It was the one connection that just wouldn't gome apart when I was taking the dash out. It's visible in this picture.

That looks like the unit inside the centre console of mine. The label that detached itself said "BMW EWS 3G" on it. For ultrasonics I would expect two units, so do you have one inside the centre console as well, Bill?

Cheers R.

[cooknerkid]

The movement sensor on my 99 facelift 2.8 is fixed to the back of the under dash trim panel above the pedals. It was the one connection that just wouldn't gome apart when I was taking the dash out. It's visible in this picture.

That looks like the unit inside the centre console of mine. The label that detached itself said "BMW EWS 3G" on it. For ultrasonics I would expect two units, so do you have one inside the centre console as well, Bill?

Cheers R.

Zed Carer -----Am I looking at the Blue Connection in the photo or the Brown unit/connected to the trim ---- If it gets as serious as your looked, I feel a trip to BMW coming on .. Anyway 2 days now of ''Double clicking'' the keyfob, and the alarm hasnt gone off . Thanks

[Zed Carer]

Zed Carer -----Am I looking at the Blue Connection in the photo or the Brown unit/connected to the trim ---- If it gets as serious as your looked, I feel a trip to BMW coming on .. Anyway 2 days now of ''Double clicking'' the keyfob, and the alarm hasnt gone off . Thanks

It's the cream/brown unit - I would have removed that piece of trim but the connection to the diagnostic socket was rock solid. Don't worry mine wasn't an alarm fault - Click for the full story!

That looks like the unit inside the centre console of mine. The label that detached itself said "BMW EWS 3G" on it. For ultrasonics I would expect two units, so do you have one inside the centre console as well, Bill?

IIRC there was a metal retangular box behind the centre console, in the centre just below the OBC, it was this box that the back of the OBC caught on when moving the centre console. This then resulted in the search for the missing Zebra strip!