W211 key fobs stopped (un)locking
Thread Starter
Junior Member
Joined: Jan 2019
Posts: 34
Likes: 1
From: Canton, MI
Saab 900 Aero, Volvo 850 R, Audi S4, MB GL 450, Buell X1, KTM 1190 Adventure
W211 key fobs stopped (un)locking
Hello all,
I have a 2004 E55 AMG that starts developing some electrical gremlins. The car sits in an underground garage and as it is not being used daily, therefore I have a main switch installed to separate the battery from the cars electric circuit to avoid battery drain.
Now some of the symptoms:
All of a sudden, the tire pressure monitoring system stopped working. As it stopped working for all four wheels, I‘d assume it is not a sensor failure, as I consider it very unlikely that all sensors stop working at the same time. Is this assumption reasonable?
This season after I reinstalled the battery (i had it removed over winter for charging), the key fobs would not unlock or lock the car. Sometimes they lock and unlock via IR, but they do not work through the radio transmitter at all.
I do not assume that the car can „forget“ the key fob sync just because the battery was removed for a few month?! Can someone confirm?
I understand the radio signal amplifier module is not only for the radio, but also for the key fobs. Is it also responsible for communication with the tire pressure sensors?
I read lots of info about faulty / corroded wiring for the radio amplifier module, but this was all related to the S211 wagons, not W211 sedans. I checked my wiring in the trunk and it all looks like new, however I have to admit that I have no idea where exactly the radio signal amplifier module sits in the W211 sedan. Can someone give me a hint.
Any ideas what diagnostics I may run or what to check to figure out what is causing the issues with the key fobs?
Best regards,
Tadek
I have a 2004 E55 AMG that starts developing some electrical gremlins. The car sits in an underground garage and as it is not being used daily, therefore I have a main switch installed to separate the battery from the cars electric circuit to avoid battery drain.
Now some of the symptoms:
All of a sudden, the tire pressure monitoring system stopped working. As it stopped working for all four wheels, I‘d assume it is not a sensor failure, as I consider it very unlikely that all sensors stop working at the same time. Is this assumption reasonable?
This season after I reinstalled the battery (i had it removed over winter for charging), the key fobs would not unlock or lock the car. Sometimes they lock and unlock via IR, but they do not work through the radio transmitter at all.
I do not assume that the car can „forget“ the key fob sync just because the battery was removed for a few month?! Can someone confirm?
I understand the radio signal amplifier module is not only for the radio, but also for the key fobs. Is it also responsible for communication with the tire pressure sensors?
I read lots of info about faulty / corroded wiring for the radio amplifier module, but this was all related to the S211 wagons, not W211 sedans. I checked my wiring in the trunk and it all looks like new, however I have to admit that I have no idea where exactly the radio signal amplifier module sits in the W211 sedan. Can someone give me a hint.
Any ideas what diagnostics I may run or what to check to figure out what is causing the issues with the key fobs?
Best regards,
Tadek
MBWorld Fanatic!
Joined: Jun 2020
Posts: 1,177
Likes: 314
2006 CLS55 AMG, 2005 SLK 350 AMG
Hello all,
I have a 2004 E55 AMG that starts developing some electrical gremlins. The car sits in an underground garage and as it is not being used daily, therefore I have a main switch installed to separate the battery from the cars electric circuit to avoid battery drain.
Now some of the symptoms:
All of a sudden, the tire pressure monitoring system stopped working. As it stopped working for all four wheels, I‘d assume it is not a sensor failure, as I consider it very unlikely that all sensors stop working at the same time. Is this assumption reasonable?
This season after I reinstalled the battery (i had it removed over winter for charging), the key fobs would not unlock or lock the car. Sometimes they lock and unlock via IR, but they do not work through the radio transmitter at all.
I do not assume that the car can „forget“ the key fob sync just because the battery was removed for a few month?! Can someone confirm?
I understand the radio signal amplifier module is not only for the radio, but also for the key fobs. Is it also responsible for communication with the tire pressure sensors?
I read lots of info about faulty / corroded wiring for the radio amplifier module, but this was all related to the S211 wagons, not W211 sedans. I checked my wiring in the trunk and it all looks like new, however I have to admit that I have no idea where exactly the radio signal amplifier module sits in the W211 sedan. Can someone give me a hint.
Any ideas what diagnostics I may run or what to check to figure out what is causing the issues with the key fobs?
Best regards,
Tadek
I have a 2004 E55 AMG that starts developing some electrical gremlins. The car sits in an underground garage and as it is not being used daily, therefore I have a main switch installed to separate the battery from the cars electric circuit to avoid battery drain.
Now some of the symptoms:
All of a sudden, the tire pressure monitoring system stopped working. As it stopped working for all four wheels, I‘d assume it is not a sensor failure, as I consider it very unlikely that all sensors stop working at the same time. Is this assumption reasonable?
This season after I reinstalled the battery (i had it removed over winter for charging), the key fobs would not unlock or lock the car. Sometimes they lock and unlock via IR, but they do not work through the radio transmitter at all.
I do not assume that the car can „forget“ the key fob sync just because the battery was removed for a few month?! Can someone confirm?
I understand the radio signal amplifier module is not only for the radio, but also for the key fobs. Is it also responsible for communication with the tire pressure sensors?
I read lots of info about faulty / corroded wiring for the radio amplifier module, but this was all related to the S211 wagons, not W211 sedans. I checked my wiring in the trunk and it all looks like new, however I have to admit that I have no idea where exactly the radio signal amplifier module sits in the W211 sedan. Can someone give me a hint.
Any ideas what diagnostics I may run or what to check to figure out what is causing the issues with the key fobs?
Best regards,
Tadek
Member
Joined: Oct 2020
Posts: 183
Likes: 41
From: Ottawa, Ontario
2013 GLK350 Canada
There might be an auxilliary battery in the trunk, have you checked for that? Can be hidden under a cover wity rug he spare tire. I've had a couple of different cars have wacky issues because of it. Some times you get an indication on the display......sometimes you don't. Also, hve you tried a new key battery?
Thread Starter
Junior Member
Joined: Jan 2019
Posts: 34
Likes: 1
From: Canton, MI
Saab 900 Aero, Volvo 850 R, Audi S4, MB GL 450, Buell X1, KTM 1190 Adventure
Thanks for the advice so far. I do not have SD, so would have to go to the dealer to get stuff diagnosed, unless there is anything i can do myself.
i will repost in the W211 AMG section, although this does not seem to be E55 AMG specific (but maybe W211 specific). I just thought that other cars may use a similar architecture, as the corresponding model years probably all have the same key fobs.
Main battery is in the trunk (no spare wheel on the AMGs of this MY) with main switch, auxiliary battery is in engine compartment, but only for SBC AFAIK.
thanks and best regards,
Tadek
i will repost in the W211 AMG section, although this does not seem to be E55 AMG specific (but maybe W211 specific). I just thought that other cars may use a similar architecture, as the corresponding model years probably all have the same key fobs.
Main battery is in the trunk (no spare wheel on the AMGs of this MY) with main switch, auxiliary battery is in engine compartment, but only for SBC AFAIK.
thanks and best regards,
Tadek
Member
Joined: Oct 2020
Posts: 183
Likes: 41
From: Ottawa, Ontario
2013 GLK350 Canada
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Without valid scan results, you are left blind.
