Now and then, my alarm goes off...very randomly. Now, it`s just been parked at the top of my drive for 2 days...and nothing. I went out earlier, parked up and it went off a couple of times.

I then got to thinking....top of the drive is level, bottom is sloped...sooooo, does it have an anti lift feature in the alarm system? Maybe it`s detecting the slope? Can this be disabled if it has got it?

I did have a quick look in the book...but didn`t find anything. Ta. Steve.

Could be the bonnet catch sensor. Common issue as the vehicle ages. Random alarm activation is a symptom. Easy DIY fix - lots of info on the forum.  2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

But never happens on the flat? Steve.

There again...when I unlock to stop alarm and then relock, the horn sounds and I just read a thread that mentions the bonnet issue. Still strange how it only goes off when on a slope  Steve.

Ahhhhh, found it in the book. Press the lock button twice within 3 seconds to disable super locking, tilt sensor and interior space protection  Steve.

bet it still goes off


Horn signals something left open. Door/boot/bonnet


Why does my neighbours f-ing 2015 Merc sound the horn every time its locked?
I'm sure its against regulators to do that these days

Only really use drivers door  Steve.

and the fuel flap...


if the bonnet switch is dodgy, it thinks its left open and sounds horn when you try and re arm

Bonnet is the most common cause for alarm going off

This happened to mine over the course of 6 months or so. I assumed it was something inside the car, like a spider crawling about, but the dealer couldn’t find anything wrong.
I eventually looked up the problem on tinternet, and sure enough, most folk solved it by changing the bonnet catch sensor. I ordered one up , and in the days before I was to collect it (it’s a full catch and built in sensor now,btw) I did the repair that many have done, which is to unhook the sensor, and bridge the female pin holes with a piece of copper wire, taped down. It’s still there, and the new catch is still in my glovebox!😂
Never had a problem since.
Cheers
Dave MY10 TDV6 SE (debadged ), Santorini Black, Flappy paddles, Privacy Glass, 20" Stormers, Mudflaps!

Gone: a comprehensive list of imprezas and a Merc ML AMG

Andy K wrote:

and the fuel flap...


if the bonnet switch is dodgy, it thinks its left open and sounds horn when you try and re arm

I only noticed the other day....that doesn`t lock  Steve.

That's the complete OPPOSITE to the instructions for L320 2010-2013 facelift models, you have to press button twice, within 3 seconds, to make the double locks, interior alarms and tilt etc become operative. I can confirm this works that way after double locking when someone was inside.  John

RRS MY12 SDV6 HSE. Sumatra Black/Ebony & Walnut + Dynamic Pack, + Cold Climate Pack + Memory Pack, Digital TV/DVD, Premium Leather, Cornering Lights, Cooler/Fridge Box, & most Options.

Yeah RRS 1 are odd.

Confused me when I purchased. Didn't think deadlocks were working.

Just 1 easy press of button though

Well, it`s been parked on the bottom of my drive for 2 nights now and the alarm hasn`t gone off. Each time I locked it I deactivated the tilt sensor by double pressing the lock button. Hopefully that`s all it was  Steve.

My 2012 model year is parked on my drive on a relatively steep slope and no false alarms. Same as earlier poster, 2 clicks on lock button fully arms, rather than disarms, everything.