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Today my E250 2014 post-facelift W212 suddenly dropped error messages on the dash and some malfunctions.
1. Active Blind Spot Assist Inoperative
2. Active Lane Keeping Assist Inoperative
3. Unable to turn on left and right turn signals using the stalk; but Hazards button still able to activate both signals
Everything else seems to be in working order at the moment.
My first and only guess is a weak battery because it has never been changed since I got it but if so, wouldn't there be a battery light on the dash? The car also starts immediately without any cranking.
Or is this a known problem and I should take it to the dealer? I don't know any indie nearby so it's gonna be a dear one.
Today my E250 2014 post-facelift W212 suddenly dropped error messages on the dash and some malfunctions.
1. Active Blind Spot Assist Inoperative
2. Active Lane Keeping Assist Inoperative
3. Unable to turn on left and right turn signals using the stalk; but Hazards button still able to activate both signals
Everything else seems to be in working order at the moment.
My first and only guess is a weak battery because it has never been changed since I got it but if so, wouldn't there be a battery light on the dash? The car also starts immediately without any cranking.
Or is this a known problem and I should take it to the dealer? I don't know any indie nearby so it's gonna be a dear one.
Any advice is much appreciated, thanks!
There is no silver bullet to fix this seemingly random problem.
I am going to volunteer the root cause is a voltage transition that disrupted a collection of CAN modules such as the distance sensors that rely on a stable environment.
The turn signal control going frozen is an unusual fault... perhaps it can lead to understanding the other faults: Shared GND -or Shared CAN Body ?
Would you be able to list all the stored DTC's as evidence to get a complete picture.
The quickest way to restore stability is to have a reliable voltage source.
The date code of your battery may be stamped on top of the NEG(-) post.
Last edited by CaliBenzDriver; Jun 13, 2021 at 07:41 PM.
Unfortunately since I am really unprepared I don't even have a OBD reader
Before engine start, 3 days unused. After engine start After engine off
This is all I have at the moment, it seems like the battery seems to be doing okay? I wonder if doing a factory reset through the speedo menu will help? If it's not a battery problem I'll have to take it to a mechanic because it's already out of my depth
Testing battery is not easy, but what you can do is in situation pictured last - turn all the headlights and blower to max.
Observe voltage drop, if it goes down more than 1 volt, it might be battery or bad connection, if it holds voltage - it is something else.
Battery light is related to alternator [charging], not battery health. As far as battery health, start by fully charging it, leave the hood propped open and the key off. After its charged, disconnect the charger and let the battery rest for a few hours. The voltage should be around 12.7-12.8 VDC for a real healthy battery. You can take it a step further, pull up the workshop menu and monitor the voltage when you start the car. You want it to stay about ~10 VDC.
Now that you have a good and charged battery, disconnect it for 10 minutes or so and then reconnect. See if your issues go away. Otherwise, take it to someone who can scan it...
Normally I would've said the battery won't matter since the alternator will keep the voltage good while driving, which has been the case on every car I've ever had or worked on, ever.
BUT, with my latest 2016 E550 it started acting weird of late, like the radio and console would not turn on when I start the car, backup camera would sometimes not work at all and then it would randomly start missing so bad it felt like only half the cyls were firing. While troubleshooting it the battery died with the Ign on for maybe 10min. Charged it overnight, started fine but same issues. Bought a new batt and everything started working again. And the Eco mode works now, which has never worked since I bought the car over a year ago. Guess I have to figure out how to disable that stupid thing now...
So somehow it knows the battery is bad despite excellent idle/running voltage. So who knows what all goes on inside that computer etc but clearly a weak battery can cause problems. I'm sure it's all programming, not an actual mechanical issue, but none the less. I'd love to be able to program all the crap like that out of this car. Sooo many annoying things about it that is 100% programming. It's like when you buy new PC that's super fast but it comes bloated with all this extra crap to ensure it's no faster than your old one, but at least those you can fix.
Hi everyone, just thought I'd give those interested an update.
I had the car looked at by a mechanic and it was diagnosed with steering column module failure. I also had the batteries looked at and they were old and weaker but otherwise still usable for a bit despite being 7yrs old.
Due to financial reasons I decided to replace both the battery and auxiliary battery for now and hold on the steering column module replacement.
The batteries were replaced and all the error messages were gone and the indicator stalk is working again. I don't know if it's a fluke or not but I'm definitely a happy camper. Hopefully it stays working!
Thanks to everyone for their suggestions!
Last edited by froztmeister; Jun 25, 2021 at 02:44 AM.
Reason: more detail
I'm sorry to not be able to send you suggestions but happy to see it's working again. I also know that battery failures could cause weird issues that might sound costly too .
However, I would take it to a reputable or certified shop because they have special computers that can scan fault codes you wouldn't see thus they could see what's stored inside the car .
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