GLS Class (X167) Produced 2020 to present

front left Malfunction after battery change 2020 GLS 450

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Old Mar 20, 2026 | 05:15 PM
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2021 C300
front left Malfunction after battery change 2020 GLS 450

I just replaced the 12V battery on my 2020 GLS 450 and had to remove the driver's seat because the battery is located under the seat. Now I am getting a Front Left Malfunction which was not the case before the replacement. I have checked the seat electrical connections several times including the yellow connector that is related to the airbags. Any suggestions to fix this issue. Thanks
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Old Mar 21, 2026 | 12:20 AM
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what do you mean by "Front Left Malfunction"? Are you referring to the airbag? If so this is 100% normal if you first removed the seat and then disconnected the battery.

You should have first disconnected the battery (you could have accessed the negative terminal when the seat in place), and THEN removed the seat and disconnected the cables.

I had this issue for the passenger side when I had to access the MBUX headunit to swap it with another one for the full carplay screen and wifi carplay. I contacted @EleBest and he cleared the airbag for the front right for me remotely. It's normal, you just need someone to clear the codes for you. I see you a newbie here. Elebest is forum vendor here and offer remove coding services. Your dealer also can clear this for you but may charge you more am not sure.
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Old Mar 21, 2026 | 12:49 AM
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Hi. Yes it is the air bag and you are correct that was the sequence I applied. I learned the lesson.
I sent a message to @EleBest asking if he can clear it for me and price. Thanks for the help
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Old Mar 21, 2026 | 12:15 PM
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Was "Registering the new battery" a possible issue in both cases mentioned above?
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