[:@]The alarm on my 2002 C230 went off by itself, stayed on for a few minutes, stopped for 1, then started again - this cycle lasted 2 HOURS!!! I disconnected the battery, but that didn't help. Can't get to the appropriate fuse (it's in the trunk) and can only unlock my driver's side door manually. Batteries in the key were replaced a month ago, so that's not the problem. PLEASE HELP!!! It's my only mode of transportation and I am NOT making friends with the neighbors. ANY IDEAS??????
Thanks!!

 

try locking the driver door with the key blade and then unlocking. usually putting the key in the ignition and starting the car takes care of the problem.....I'm sorryyou did say it wont start, the problem I'm talk ing about you can still start the car, but the alarm keeps on sounding.

 

there is problems with the alarm siren itself. right side wheel well liner you will need a tamper proof torx and then you can remove the alarm siren then it wil be quiet. but you need to put the alarm siren someplace else because it will keep going off.

 

I had the same problem. So I hear you with the neighbors… I have taken my car to the dealer and dealer could not find any thing wrong, but they suggested to change the siren it self, and with clearing all the old codes, cleaning/ changing connectors it took care of the problem. I also suggest if you decide to take it to dealer, ask them to change the connectors for you. The cost was around $400 USD for changing the siren at the dealer and I got a loaner car while MB dealer was working on that.

Also a suggestion oncutting off thealarm, is to get inside the car and use the lock/unlock button in the car few times. This was helpful sometimes for me.


Please give me an update.

Thanks
KenZ

 

chassis221 - I have the same alarm problem as eweaver, but something I don't understand - if the siren is removed, why would it keep going off?

 

It keeps going off because it has a back-up battery built-in the siren. Replace the Alarm Siren and clean off the connectors...

take care
-mar-

 

Does dosconnecting the battery help at all?

 

NO it won't because the back-up battery is built-in with the Siren. It's design so if someone disconnects the CAR battery, it will still go off.

take care,
-mar-

 

Then that's not the problem I'm having. When I disconnect the negative battery cable, the siren goes off.

Additionally, I measured the voltages on the 3 connector pins - One is Ground, another appears to be Battery Positive (12.60 volts) and the 3rd is close to Battery Positive (from the ECU?) that's a bit less than Battery at around 12.1 volts.

It appears that there is an actual continual alarm condition.