Alarm going off and key fob not working...

JohnT360

Member
 West Midlands
Hi Guys,

I'm new to the forum so hi to all.

My problem is, my alarm keeps going off now and again and then this morning my key fob wouldn't work (both sets). I opened the car door just with the normal key and the alarm went off until I put the key in the ignition (normal). I drove to work and then tried the key again and it work (opened and closed the doors). Just as I was walking away from the car the alarm went off again...

Any thoughts ?

Cheers
John
 
Welcome :D

Alarm could be the bonnet sensor - easy and cheap to replace - do a search :thumbsup:

Key could be lack of charge...
 
Hi Gannet, thanks for your reply....

Yeah I did find info about the bonnet sensor but thought it might be a different problem due to the keys not working. I'll be picking up my new sesor later today only £10.40.
Guess I'll have to see if it sorts it out.

Cheers
John
 
Hi John,

I had a simialr prob with mine. Dealer said they had seen this before when water gets into the alarm siren. They put a new one in and sealed with tape - been fine since. You could try sitting the siren on a radiator for a while and then make it watertight. Don't know where the siren is I'm afraid, but I'm sure someone here will.

Regards.
 
Thanks for your reply noisy... I've changed the bonnet sensor like gannet suggested but I still get the keys not working. BMW want £90 just to look at it so I wanted to see if anything else could be wrong. I'll try and find where the siren is.

Cheers
John
 
Took mine to the dealer for the same problem (alarm keeps going off every 5 mins, hasn't been armed for about 3 weeks!).

The mechanic I spoke to was really helpful, first off thought it would be the tilt-sensor, and even ordered a replacement. Turns out after diagnostics to be the bonnet sensor, so is going back in next week for replacing.

Don't know if that helps, but good luck fixing it.
 
Hi Guys,

Thought I would give you an update...

I have fixed the problem after trying many things. The alarm going off was due to the bonnet sensor and only cost me £10 for the part and seconds to replace. My main key's battery had gone so I found a replacement on eBay (£6) and then carefully opened the key and replaced the battery (do not solder it in as it can explode when hot) and super glued it back together.

I then used my spare key for a week so it charged up (still didn't open the doors) and then put it in the ignition and turned it one click and then back out very quickly, then put the main key in (new battery key) turned it one click and then back out and held the 'Lock' button down and pressed the 'unlock' button 3 times and then let go of the 'lock' button. The locks on the car then closed and opened to say it's been programmed. With that key now programmed I did the same on the other key and they both now work.

I hope that makes sense...

It's very easy to change the battery in the Key so if you need help just email me and I'll try to help.

Cheers
John
 
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