SOS Inoperative
Member
Joined: Mar 2003
Posts: 188
Likes: 78
From: Toronto, Canada
GLC300 (mine) GLK250 (wife's)
You're going to have to be a bit less sketchy with your info. Model/year, what did the dealer tell you/do/not do, what are your symptoms if any? etc etc...
Your dealer being "useless" isn't much to go on.
Your dealer being "useless" isn't much to go on.
Thread Starter
Newbie
Joined: Oct 2018
Posts: 14
Likes: 0
From: Kansas
2014 C300
2014 GLK 350. 4Matic. The dealer advised they would only replace the tele module. They claimed they had not seen it before. I don’t feel they know what they are talking about. I don’t want to throw parts at it either.
Member
Joined: Mar 2003
Posts: 188
Likes: 78
From: Toronto, Canada
GLC300 (mine) GLK250 (wife's)
Usual dealer approach - throw parts at the problem and hope for the best.
If you have a warning light you probably have a fault code which you can read to pinpoint the issue. If you have a code reader you could do this yourself. If not try a reputable indy with the necessary MB diagnostic expertise. Do you have any symptoms or is it just the warning light?
If you have a warning light you probably have a fault code which you can read to pinpoint the issue. If you have a code reader you could do this yourself. If not try a reputable indy with the necessary MB diagnostic expertise. Do you have any symptoms or is it just the warning light?
Thread Starter
Newbie
Joined: Oct 2018
Posts: 14
Likes: 0
From: Kansas
2014 C300
It doesn’t throw a code. It only pops up on every start up of the engine. Just pops up as a SOS Inoperative. I don’t have a shop around here aside from the dealer. I called one that was about an hour away that wanted me to leave the car and he would fit it in. They thought it would be a week plus. I didn’t want to take that route.
Member
Joined: Mar 2003
Posts: 188
Likes: 78
From: Toronto, Canada
GLC300 (mine) GLK250 (wife's)
Found this potential fix. Can't confirm it works but worth a try.
To turn off the SOS warning, shut off the engine and then turn the key back on. Then turn on the headlights and leave them on for two minutes. Then turn them off and turn off the key. The message may still there at the time but will be gone the next morning. It has to do with the brain box having a battery voltage question and by burning the headlights for two minutes, the brain box sees a voltage drop and records the new battery voltage.
To turn off the SOS warning, shut off the engine and then turn the key back on. Then turn on the headlights and leave them on for two minutes. Then turn them off and turn off the key. The message may still there at the time but will be gone the next morning. It has to do with the brain box having a battery voltage question and by burning the headlights for two minutes, the brain box sees a voltage drop and records the new battery voltage.
Thread Starter
Newbie
Joined: Oct 2018
Posts: 14
Likes: 0
From: Kansas
2014 C300
So I tried the above and it didn’t fix the issue. I put a battery tender on the main battery and it took a long time to get to the maintain only spot. After running the vehicle. It goes right back to needing a lot of charge. I’m thinking it is the battery going bad. Maybe both? I’m not sure what runs what.
Trending Topics
MBWorld Fanatic!
Joined: Sep 2015
Posts: 2,583
Likes: 342
2013 glk 350
I’ll bet your battery is original and weak, weak batteries cause a lot of problems even damage to electronics. Get it tested and probably replaced. If it’s original and as you said was hard to charge just replace it with a AGM battery. Most all auto parts stores test for free and some instal, I just replaced mine.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Newbie
Joined: Oct 2018
Posts: 14
Likes: 0
From: Kansas
2014 C300
Both batteries are AGM. So I will look into replacing those. Is there a brand people prefer?
it shows SOS Inoperative and the telephone symbol. And all the lights on the ceiling are lite up. The SOS, emergency, and call light.
I think the batteries are bad. I’ll get them out and tested ASAP.
it shows SOS Inoperative and the telephone symbol. And all the lights on the ceiling are lite up. The SOS, emergency, and call light.
I think the batteries are bad. I’ll get them out and tested ASAP.
Newbie
Joined: Jun 2024
Posts: 1
Likes: 0
a class 180d 2018
Found this potential fix. Can't confirm it works but worth a try.
To turn off the SOS warning, shut off the engine and then turn the key back on. Then turn on the headlights and leave them on for two minutes. Then turn them off and turn off the key. The message may still there at the time but will be gone the next morning. It has to do with the brain box having a battery voltage question and by burning the headlights for two minutes, the brain box sees a voltage drop and records the new battery voltage.
To turn off the SOS warning, shut off the engine and then turn the key back on. Then turn on the headlights and leave them on for two minutes. Then turn them off and turn off the key. The message may still there at the time but will be gone the next morning. It has to do with the brain box having a battery voltage question and by burning the headlights for two minutes, the brain box sees a voltage drop and records the new battery voltage.
Super Member
Joined: Feb 2023
Posts: 728
Likes: 271
2011 GLK 350 4Matic
MBWorld Fanatic!
Joined: Jan 2024
Posts: 2,515
Likes: 900
From: DFW
SL63
I had the problem, talked about it on another SOS inop thread.
The dealer loaded the most current software update, and it has reduced the incidence to a minimum.
I found in another thread, that others had the issue, and it was moisture related.
Some moisture around the headlight cases. That was resolve by having the headlights on for 2 minutes without the engine running.
The other problem area was in the trunk where moisture was getting into some electrical connections.
The dealer loaded the most current software update, and it has reduced the incidence to a minimum.
I found in another thread, that others had the issue, and it was moisture related.
Some moisture around the headlight cases. That was resolve by having the headlights on for 2 minutes without the engine running.
The other problem area was in the trunk where moisture was getting into some electrical connections.
Member
Joined: Jun 2015
Posts: 167
Likes: 30
2013 GLK350
I had this issue. When it happened, I thought it was the module that calls out, using old 3g tech that is no longer available on any US cell networks. I lived with it a while.
Then I brought the car to a local independent mercedes shop. I was going to have them disconnect the module, so the message didn't come up any more. They said they didn't need to do that. They just cleared the codes in the system and the message went away. Hasn't come back in a year of driving.
This is for a GLK. Your car is different so probably should post in a different forum
Then I brought the car to a local independent mercedes shop. I was going to have them disconnect the module, so the message didn't come up any more. They said they didn't need to do that. They just cleared the codes in the system and the message went away. Hasn't come back in a year of driving.
This is for a GLK. Your car is different so probably should post in a different forum
Last edited by mogulman; Jun 10, 2024 at 06:41 PM.
MBWorld Fanatic!
Joined: Jun 2021
Posts: 1,008
Likes: 280
From: South Texas
2014 GLK350 base model (active) ; 2001 E320 base (retired); 2001 Wrangler soft-top
quote: ****Major U.S. network providers**** plan to decommission their 3G networks in **2022**".
This will affect your Mercedes-Benz mbrace services if your vehicle is 2016 and prior and select 2017 models.
https://www.mbusa.com/en/owners/3g-network-sunset
