Alarm going off !

[James72]

Hello All,

New member from Devon

Recently purchased a 2006 Coupe sport, absolutely loving it.

I was pre warned by the seller that the alarm goes off randomly, so not a complete surprise, it seems quite common after searching around here.

So I’ve disconnected bonnet sensor and it is still going off randomly!

I am currently just pressing the lock button on the fob twice to switch off the sensors and whilst this stops it going off, I’d like to sort it.

Any suggestions greatly appreciated

Cheers

 

[wonkydonkey]

There's a weird thread somewhere on here about coins in the centre console/ashtray setting the internal sensors off. Do you have coins resting there?

 

[Tcochrane92]

Bonnet switch - rear of engine bay. Disconnect it and see if it stops

 

[kis]

I'd second the coins, not very common but it was the issue for mine. Was in the centre console below the handbrake. But as a precautionary measure check the entire console and remove anything shiny and fingers crossed this works for you!

 

[James72]

Yeah I did read something about coins, none in the car at all and nothing in the ashtray !

 

[Jollyjoiner]

Yep another one here suggesting bonnet switch

 

[James72]

Yep, as I said already disconnected the bonnet switch

 

[kis]

Done any diagnostics? Sure it should show up on there...

 

[James72]

Not yet, taking it to a friends garage at the weekend to get it plugged in.

 

[ben g]

Interested to see what the cause of this one is. I replaced my bonnet alarm switch a couple of weeks ago and last week I was rudely awakened by my car alarm going off again my ring doorbell picked up no cats or other animals jumping on the car, so I'm really at a loss as to what it could be.

I didn't realise the 2 presses on the lock button disables the interior sensors. It hasn't gone off since that one time last week, so perhaps it was just a one off? Either way, hoping you get an answer so I can too

 

[kis]

I'd be interested too! awakens the inner Holmes in me :lol:

 

[brillomaster]

not sure if the same applies to a z4 coupe but certainly on a similar vintage bmw 3 series its pretty easy to unclip the cover and disconnect the interior motion sensor.

indeed the first thing I did a while back on an old 3 series I bought was disconnect the open bonnet sensor and the interior motion sensor, just in case it caused a problem.

 

[oldgitdave]

Low battery was the cause of my E85 alarm going off randomly. If I'm not driving it for more than a couple of weeks I put it on the Ctek. Not had an issue since.

 

[kis]

The system monitors the foot-wells and the seating areas of the driver and passenger. Even when the convertible top is open, the alarm system including the interior motion sensor is armed. Objects falling into the vehicle, e.g.leaves, can trigger unintentional alarms.

So I've got possible culprits:

• Bonnet Sensor

• Interior Sensor

• Tilt Sensor

• Low Battery

Tried to find the location of the interior sensor, as that's what it's most likely to be. But couldn't. Also read somewhere that if the windows aren't up fully on a coupe it won't arm the interior sensor (but the tilt sensor should still be active - maybe!) so could uses this to help identify whether its interior or tilt (try jacking it up, locked but windows open). Personally doubt it's the battery as seems to be an ongoing thing and it "behaves" when you double lock it.

 

[James72]

I was thinking battery but wasn’t convinced as it is fine with the double lock.

So I had a read of the owners manual, and the double lock, disables the interior and tilt sensor so assume it’s one of them. Hopefully it will show up when I get it plugged in. I could just code them out I suppose.