Alarm issue
Thread Starter
Newbie
Joined: Mar 2024
Posts: 3
Likes: 0
From: Central Texas
2004 E55 AMG
Alarm issue
2004 E55 AMG, stock aside from an aftermarket radiator and a BMW PS reservoir for a coolant tank on the SC.
I’ve got an unusual alarm issue.
Im new to these cars (been reading around this forum a bit though), I bought this pretty close to a year ago. Within a few weeks of ownership I was on the highway and the alarm went off while driving. I pulled off onto a chain up station, shut the car off, hit the unlock button after opening the door and continued on my way.
2 months after that, similar thing in a new state/new house.
5 months later my wife accidentally had the key in her pocket and washed it. When I finally found it, it didn’t work. I took it apart, threw it in a bag of rice for a few days and replaced the batteries. The key works fine now, exactly as before but this alarm issue has come back with a vengeance. If I make a 15 mile drive down the road I might have to stop 3-4 times to get the alarm to shut off, or ignore it because it will go off for 3-30 seconds at a time. The buttons on the key don’t seem to do anything while it’s driving.
I did a little digging online and someone mentioned a weak battery will cause this, I hooked up a cheap monitor to the OBDII to monitor while driving and voltage is anywhere from 13.88-14.06v. It hasn’t set the alarm off again while monitoring voltage. I’m unsure if there is a random drop in voltage sporadically that would cause it.
Last night, my parents in law were over for dinner and on the way out my FIL said the interior light was on. Car was locked and after opening and closing and relocking the car, the light was off. Around 1am, I woke up to the alarm going off. I grabbed the key and ran towards the front of the house until it was within range.
Ive read online that the PSE can be an issue, but other than the alarm going off and that weird light problem (that has only happened once as far as I know, I’m not sure if the lights are even part of it), everything else is normal.
Any thoughts on the direction I should go initially without parts bombing it?
I’ve got an unusual alarm issue.
Im new to these cars (been reading around this forum a bit though), I bought this pretty close to a year ago. Within a few weeks of ownership I was on the highway and the alarm went off while driving. I pulled off onto a chain up station, shut the car off, hit the unlock button after opening the door and continued on my way.
2 months after that, similar thing in a new state/new house.
5 months later my wife accidentally had the key in her pocket and washed it. When I finally found it, it didn’t work. I took it apart, threw it in a bag of rice for a few days and replaced the batteries. The key works fine now, exactly as before but this alarm issue has come back with a vengeance. If I make a 15 mile drive down the road I might have to stop 3-4 times to get the alarm to shut off, or ignore it because it will go off for 3-30 seconds at a time. The buttons on the key don’t seem to do anything while it’s driving.
I did a little digging online and someone mentioned a weak battery will cause this, I hooked up a cheap monitor to the OBDII to monitor while driving and voltage is anywhere from 13.88-14.06v. It hasn’t set the alarm off again while monitoring voltage. I’m unsure if there is a random drop in voltage sporadically that would cause it.
Last night, my parents in law were over for dinner and on the way out my FIL said the interior light was on. Car was locked and after opening and closing and relocking the car, the light was off. Around 1am, I woke up to the alarm going off. I grabbed the key and ran towards the front of the house until it was within range.
Ive read online that the PSE can be an issue, but other than the alarm going off and that weird light problem (that has only happened once as far as I know, I’m not sure if the lights are even part of it), everything else is normal.
Any thoughts on the direction I should go initially without parts bombing it?
MBWorld Fanatic!
Joined: Jan 2014
Posts: 3,978
Likes: 1,322
From: Republic of Texas
'99 and '05 E55 AMG
The battery internal to the alarm is bad and/or corroded circuits in the alarm. Pull passenger side fender liner, remove and discard old alarm, install new alarm.
MBWorld Fanatic!
Joined: May 2022
Posts: 1,917
Likes: 499
From: The Netherlands
2005 CLS55 AMG W219 C219
My guess as well, a new alarm siren was about 145 euros in the Netherlands. I replaced it not too long ago, see my build thread for partnr and extended pictures > https://mbworld.org/forums/c219/8443...ml#post8904354
