Alarm going off

[Nellybauer]

Last couple of days in the heat, my alarm has gone off with nobody around the car, once yesterday, twice today so far. I can then just unlock and lock the car and it's all good.

Is this a known issue at all or perhaps somehow related to the heat?

I was also having issues with unlocking the drivers door via the key fob button, but that seems better for the last few days, not sure if could be related?

 

[enuff_zed]

Last couple of days in the heat, my alarm has gone off with nobody around the car, once yesterday, twice today so far. I can then just unlock and lock the car and it's all good.

Is this a known issue at all or perhaps somehow related to the heat?

I was also having issues with unlocking the drivers door via the key fob button, but that seems better for the last few days, not sure if could be related?

Usual culprit is the plunger in the middle of the engine bay on the bulkhead. Try unplugging that.

 

[Nellybauer]

Usual culprit is the plunger in the middle of the engine bay on the bulkhead. Try unplugging that.

Ok, so leaving it unplugged won't make it think bonnet is open?

 

[enuff_zed]

Ok, so leaving it unplugged won't make it think bonnet is open?

No, just pull the connector off and tuck it back out of the way.
Does mean if someone steals your engine you won't know.

 

[tomscott]

Super common will be fine

 

[Nellybauer]

Disconnected the bonnet connection, but just had the alarm go off twice even with that disconnected. Anything else I should check?

 

[enuff_zed]

Disconnected the bonnet connection, but just had the alarm go off twice even with that disconnected. Anything else I should check?

Ideally then you need a code reader to tel you what part of the system is activating

 

[Rocket]

If it is causing annoyance to neighbours etc. you can disable the sensors.

To quickly disable the interior motion and tilt sensors on your BMW Z4

1. Exit the vehicle and close all doors and windows.
2. Press the Lock button on your key fob once to lock the car.
3. Press the Lock button again within 10 to 30 seconds.

This action disables the interior motion and ultrasonic sensors while keeping the exterior sensors (doors, hood, trunk) armed.

How to verify it worked:
Look at the red alarm LED (usually located on the bottom of the rearview mirror). When you press the lock button that second time, the red LED will light up continuously for about 2 seconds, and then begin flashing briefly. This continuous light is your visual confirmation that the interior and tilt sensors are turned off.

 

[enuff_zed]

I ‘think’ if you lock the car with the key in the door it doesn’t set the alarm?

 

[Rocket]

I ‘think’ if you lock the car with the key in the door it doesn’t set the alarm?

I think that is correct.

 

[TriggerFish]

I ‘think’ if you lock the car with the key in the door it doesn’t set the alarm?

I don't think that's correct (or maybe it's a coding setting, but I can't remember if that's just for the key disarming the alarm), as my car beeps when the alarm is armed, and it beeps when locked with the key.

 

[enuff_zed]

I don't think that's correct (or maybe it's a coding setting, but I can't remember if that's just for the key disarming the alarm), as my car beeps when the alarm is armed, and it beeps when locked with the key.

Ah ok. Was just something I’d heard somewhere

 

[TriggerFish]

No worries

I was testing the key lock a lot recently when replacing the door lock actuator, so it was fresh in my mind.

The double-tab-the-lock-button from Rocket is a good shout though - that's called out in the handbook, so is definitely a legitimate route.

 

[SimonR]

@colb has mentioned several times that locking the car manually with the key doesn't set the alarm sensors - worked for me when my alarm kept going off.

 

[enuff_zed]

@colb has mentioned several times that locking the car manually with the key doesn't set the alarm sensors - worked for me when my alarm kept going off.

I have had ther same experience.
Yet, I've just consulted the manual and it says using the key still sets the alarm???

 

[colb]

On my 2007 2.0l and my previous 2.5 using the key to lock the car in the door lock didn't set the alarm, confirmed by no flashing light in the clowns nose on the rear view mirror.

 

[Nellybauer]

If it is causing annoyance to neighbours etc. you can disable the sensors.

To quickly disable the interior motion and tilt sensors on your BMW Z4

1. Exit the vehicle and close all doors and windows.
2. Press the Lock button on your key fob once to lock the car.
3. Press the Lock button again within 10 to 30 seconds.

This action disables the interior motion and ultrasonic sensors while keeping the exterior sensors (doors, hood, trunk) armed.

How to verify it worked:
Look at the red alarm LED (usually located on the bottom of the rearview mirror). When you press the lock button that second time, the red LED will light up continuously for about 2 seconds, and then begin flashing briefly. This continuous light is your visual confirmation that the interior and tilt sensors are turned off.

Thanks, can confirm the led did stay lit for a couple of seconds. Alarm hasn't gone off again yet since will keep an eye on it.

The LED in the rearview does seem to be missing a bit of trim around it, maybe someone has played around with it before.

Knowing how forgetful I am, I'll probably keep only single locking and have the alarm go off frequently! Have got an OBD2 reader arriving soon, may see if can dig into it any further

 

[smorris_12]

It'll be a codeable option somewhere in the GM5. My E46 didn't set the alarm with the key and the clown nose stayed off. I don't think it set the double locking either. The Z4 is the opposite (which I find a nuisance) but I presume was chosen as the default because of being a convertible.