Talk to H&P and describe the symptoms, they were helpful with me. Jim is the guy who knows what's what.

The alarm is 8 years old on your car so done well!!

I had a number of problems, culminating in very similar to your problems. Using the key didn't resolve it as it re-armed itself. I think you need to unlock, open door, turn ignition on then lock with key in door. Missing the opening door/ignition on resulted in re-arming for me.

Int he end, I got a replacement board (which I fitted - straight swap but fiddly) from H&P and it's been fine ever since, touch wood. Certainly a lot cheaper (£190 IIRC delivered with new fob, I returned old board which will give me back £25 if it's serviceable). Certainly a lot cheaper than a replacement alarm.

 

Just to confirm that your symptoms are exactly the same as mine, drove us mad for quite some time as the whole thing was so random. No pattern to when the siren would sound nor to length of time between bouts.

Am now just using key in door to lock car, immobiliser works but siren disabled. Peace and quiet at last.

Will have to follow Dracoro's advice/plan sooner or later. mine is a 2003 by the way.

 

Could be that your battery is running low. Go for a 30 min drive and see if that helps?

 

See OP!

I'm slightly confused this morning, as we had an undisturbed night, with no false alarms. To check if locking the door with the key meant that the alarm was not enabled, this morning I opened the boot with the key and the alarm immediately went off. This would suggest that the alarm had actually been active overnight!

The car is now locked from the key fob and I shall see what happens during the course of the day.

 

Good luck Dennis!

 

the sensor/switch under the bonnet. mine used to get wet and go off. grease that up.

 

Read OP.

You're right though, this is a known trouble spot!

 

I had this on my Type R, kept going off at night! No fault codes showed up or anything, Honda had the car for 3 weeks! I think in the end it was something to do with the sensor by the rear view mirror!

 

Previous owner of my car (MY02) had this problem, I think Honda ended up replacing the entire alarm system at great cost to them.

 

I'd suggest shorting of the bonnet switch (water ingress) as the likely culprit.

You clould try removing the bonnet switch entirely & taping off the wire - see if that fixes it.

I had to braze the 'Lude's back together due to corrosion recently.