SL/R231: First Issue..Key Not Recognized
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Joined: Jul 2009
Posts: 503
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From: Miami Beach
2006 CLS55 AMG Sold 2010 E550 Coupe totaled by mechanic, '13 SL550 I totaled it, 2017 SL63 current
First Issue..Key Not Recognized
Not sure what it is with Mercedes and the key not being recognized. Happened in my E550 Coupe as well. Two days ago, Key in my pocket, door unlocks, get in, Dash says key not recognized. I pushed the starter a few times, nothing. Then a message on the dash says to pull the start button out and insert key. As I pulled the button out, the car starts. I though that was a bit bizarre but I go to put the car in drive and it won't go in. I tried reverse, drive etc and nothing. Shut the car off started it with the button and everything was back to normal. One of the first things I did was change the key fob batteries to the ones recommended here, I believe Panasonic but that isn't the culprit. Has anyone diagnosed the actual issue with the system? What is up with MB and the unrecognizable key??
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Not sure what it is with Mercedes and the key not being recognized. Happened in my E550 Coupe as well. Two days ago, Key in my pocket, door unlocks, get in, Dash says key not recognized. I pushed the starter a few times, nothing. Then a message on the dash says to pull the start button out and insert key. As I pulled the button out, the car starts. I though that was a bit bizarre but I go to put the car in drive and it won't go in. I tried reverse, drive etc and nothing. Shut the car off started it with the button and everything was back to normal. One of the first things I did was change the key fob batteries to the ones recommended here, I believe Panasonic but that isn't the culprit. Has anyone diagnosed the actual issue with the system? What is up with MB and the unrecognizable key??
Out Of Control!!
Joined: Sep 2018
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From: unbegrenzt
2017 GLE350 4MATIC
Not sure what it is with Mercedes and the key not being recognized. Happened in my E550 Coupe as well. Two days ago, Key in my pocket, door unlocks, get in, Dash says key not recognized. I pushed the starter a few times, nothing. Then a message on the dash says to pull the start button out and insert key. As I pulled the button out, the car starts. I though that was a bit bizarre but I go to put the car in drive and it won't go in. I tried reverse, drive etc and nothing. Shut the car off started it with the button and everything was back to normal. One of the first things I did was change the key fob batteries to the ones recommended here, I believe Panasonic but that isn't the culprit. Has anyone diagnosed the actual issue with the system? What is up with MB and the unrecognizable key??
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Joined: Feb 2021
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
Not sure what it is with Mercedes and the key not being recognized. Happened in my E550 Coupe as well. Two days ago, Key in my pocket, door unlocks, get in, Dash says key not recognized. I pushed the starter a few times, nothing. Then a message on the dash says to pull the start button out and insert key. As I pulled the button out, the car starts. I though that was a bit bizarre but I go to put the car in drive and it won't go in. I tried reverse, drive etc and nothing. Shut the car off started it with the button and everything was back to normal. One of the first things I did was change the key fob batteries to the ones recommended here, I believe Panasonic but that isn't the culprit. Has anyone diagnosed the actual issue with the system? What is up with MB and the unrecognizable key??
Definitely check the aux (and main) battery.
I would make sure it’s not a FOB issue. Doubtful, but worth isolating none the less for diagnostic purposes. If your car came with 2 FOB’s make sure the one you’re not using is out of range of the car. The fact that it wasn’t shifting even though the car started points to possible AUX battery circuit issue. Those functions will typically become problematic if Aux battery is low.
How long has it been sine you checked the Aux battery? Make sure it’s either load or resistance tested not just checked for voltage.
If you know someone with XENNTY it will show you the battery status and if it fails or passes internal resistance testing.
Since your e550 is doing the same thing and it’s happening at home, there could be some weird interference thing going on but more than likely it could be the Aux battery in that car too…
Good Luck!
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Joined: Jul 2009
Posts: 503
Likes: 95
From: Miami Beach
2006 CLS55 AMG Sold 2010 E550 Coupe totaled by mechanic, '13 SL550 I totaled it, 2017 SL63 current
I just purchased the car in March. As per the car fax, the battery was replaced on 12/18/20. It doesn't mention which battery so most likely the main battery. I will have the Aux battery tested, I didn't even think about that. Much appreciated Gentlemen.
Thread Starter
Super Member
Joined: Jul 2009
Posts: 503
Likes: 95
From: Miami Beach
2006 CLS55 AMG Sold 2010 E550 Coupe totaled by mechanic, '13 SL550 I totaled it, 2017 SL63 current
So a follow up, I have not replaced the aux battery yet or had the time to get it load tested. I am just going to replace it in the upcoming week or so. On occasion, when I approach the car with fob in my pocket the car will unlock but when I open the door the alarm will go off for a second and stop. My gf has the other fob and she says it never happens to her. Next, my tpms is showing a fault even with 38 front-36 rear psi. Just curious if all related to aux, but regardless I am looking online now to purchase. Found original MB for $129 at Autohaus. If any other recommendations on where to purchase, I welcome suggestions. Always greatly appreciate the insight and assistance! Overall, it's been a fantastic almost 6 months with the car. Little nuisances are what they are and have zero retraction on my proud ownership.
Joined: Nov 2016
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
My daughter has this weird aura about her where highly sensitive electronics will randomly fail. She had an Audi A4 that switched the default language for the display on it's own. When she goes to the doctor's office, some test equipment will randomly fail. And don't even ask about her experience with computers! Needless to say, she doesn't come near my cars. (I also had a brother who could only wear self-winding watches -- the battery powered watches would always fail.)
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Thread Starter
Super Member
Joined: Jul 2009
Posts: 503
Likes: 95
From: Miami Beach
2006 CLS55 AMG Sold 2010 E550 Coupe totaled by mechanic, '13 SL550 I totaled it, 2017 SL63 current
My daughter has this weird aura about her where highly sensitive electronics will randomly fail. She had an Audi A4 that switched the default language for the display on it's own. When she goes to the doctor's office, some test equipment will randomly fail. And don't even ask about her experience with computers! Needless to say, she doesn't come near my cars. (I also had a brother who could only wear self-winding watches -- the battery powered watches would always fail.)
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