A-Class alarm.. tripping for no reason, on the move.

[Helmet Vonthrob]

I've got a 01/51 170CDi and electrically everything works fine... except:- every so often, I will unlock the car, get in, start it up drive off and get 50 Yards (sorry 91.5m) and the alarm goes off, the only way to reset it is to pull over, switch off, remove the key and 'unlock' the car with the remote from the driving seat.

This doesn't seem to happen all the time or even every Friday morning anyone got any ideas?

I did see it happen to someone else a few days ago so it must be a common-ish problem

 

[mioba]

I've got a 01/51 170CDi and electrically everything works fine... except:- every so often, I will unlock the car, get in, start it up drive off and get 50 Yards (sorry 91.5m) and the alarm goes off, the only way to reset it is to pull over, switch off, remove the key and 'unlock' the car with the remote from the driving seat.

This doesn't seem to happen all the time or even every Friday morning anyone got any ideas?

I did see it happen to someone else a few days ago so it must be a common-ish problem

who was the somone else and what did they find!

 

[Helmet Vonthrob]

The someone else

... was a woman who drove off down the street; I couldn't get to her before she restarted and drove off.

 

[Helmet Vonthrob]

Anyone...

Sorry to bump this guys but it happened again last week... I can't put any kind of pattern to it.. anyone?... anyone?????

 

[D3Less]

I had an 02 reg A class for a short while and this happened to me. Dealer said it was the remote needing new batteries.
Can't remember for sure whether this cured the problem but might be worth a try.

 

[pcman_jh]

A Class alarm tripping - I could be the someone else!!

I posted a message at New Year about a friend's A class that had similar issues, except his was preceeded by the keyfob not opening the car remotely. It would open and start wiht the key, but the alarm would be triggered.

Someone replied to say if the batteries in the keyfob are changed it needs syncing to the alarm system (details of the reset process are in the car's handbook)

The guy phoned me yesterday to say that he performed the process and only after trying it a few times did it start working, with the first few attempts only remotely working if held close to the car, then without warnig it fully started working from normal distances (>20 feet). He even put hte old keyfob batteries back in and it's still working!! Answers on a postcard to...

Hope this helps.

 

[type49]

Some A classes used to suffer from ignition barrels getting stiff. When this happens, it's very easy to grip the key a bit harder to turn it and you accidently lock the car as you start it up. These alarms are more basic than the factory MB type and can arm with the ignition on. Just before you next start up, see if your thumb is on the lock button - I bet it's closer than you think.

 

[The Hooded Claw]

My old Omega used to do this all the time I eventually traced it to a loose connection on the courtesy lights .......the alarm was wired into this light circuit so every time you opened the door & the light came on the alarm dectected a curret flow & triggered the alarm.......i only noticed it when the alarm went off whilst driving out of my drive at night..the interior light came on (Flashed) for a split second before the alarm triggered .........By the way the loose connection was on the boot switch ......so don't just try the doors!!!