I took my 2017 E43 to the car wash yesterday. I did both the touchless automatic and the manual bay because I wanted to spray the dirt that had built up in all the door jambs and other crevices. I also used the low pressure rinse to try and clean under the hood. Note that I did not spray the engine and I tried not to spray any electronics or wires. I only sprayed the bottom of the hood and some metal support I saw in the engine bay that was dirty but not any engine components, although some water did drip. Note that I also used the high pressure wash to clean behind the wheels and fender liners. As I was pulling away I got an error stating wheel sensors missing and none of them have any readings. Note that the LF one has been out since I bought the car and the other day when I started the car before work my RF didn't have a reading either. But after work it was working again. I tried resetting the system and it did nothing. A few hours later, all but the LF started working again. Now I just received a message stating it couldn't read the tire pressure but when I pulled the TPMS screen up my rear tires were showing values. Also, after the wash the power close on the trunk stopped latching! It's like the soft close part isn't doing anything. I had just grabbed some things out of the trunk before the car wash and it was working fine. I can't help but think I got something wet. Perhaps the TPMS is problem is coincidence as it was already acting up. Any thoughts?

 

They probably just need to get replaced. Stop by your local tire shop and they have a handheld that can detect them.

 

You sprayed the door jambs?

consider this:

you got a wire bundle wet and it's affecting a SAM or BCM or canbus signal ... check for water under the (illuminated) door sills and your best bet is to dry things out asap... lots of wire looms run along the door sills, check for any interior water at the drivers and passenger footwells

also check for codes with a good scanner and you can possibly isolate the module that is barking

 

All four? I suspected the front two needed replacement but it seems weird the whole system went out immediately after washing the car.

Hmm. I actually meant to have them scanned Friday. I'll swing by a tire place today.

Oh, no. This is what I feared.

I thought everything was well protected and wrapped. I'll investigate more and post back.

I don't have a good scanner though. I'll have to see about getting it scanned. The car is going back to the shop to get the driveshaft flex disc replaced in a couple weeks but maybe they can squeeze me in before that.

 

You're right, probably not all four. I missed that somehow. Peter Uber provides sound advice. Hope you get it resolved.

 

Here's something interesting though. I forgot to mention, when I had my tires put on last week, my shop was unable to scan any of the wheel sensors. They said they tried three different devices.

I just stopped at Farm and Fleet and they were unable to scan any of the wheel sensors either. The guy scanning the tires said it didn't matter if he tried to scan it as an E43 AMG or a standard E Class. He said they've had E Classes in their service center before and were able to scan the sensors just fine.

He suspects that my sensors are so low in power that external devices are unable to communicate with them but sometimes the systems in a vehicle are able to function with much lower voltage so that could be why I'm still getting readings. I'm not sure if that's true or not but it's what he said.

 

I would not ever advise to throw money at parts at a car without a proper diagnosis at minimum with a good scanner to scan for codes, however, I'm curious when you last changed the main battery and the auxiliary battery in this vehicle

 

Everything feels perfectly dry. I tried to remove the illuminated AMG trim piece with a plastic trim removal tool but I started to bend the metal. Fortunately, I was able to gently tap it back in place and roll the fold. I dodged a bullet there and I'm too scared now to try again.

I don't think I actually sprayed up to those rubber wire concealer things. They are all in very good condition too. I would think they would be able to tolerate light sprays without water getting in... But here I am.


According to the service records the battery was changed at the end of January this year when it had its 70K service done at 69k. The car now has 82K on it.

I don't see anything in the service records about the auxiliary battery being changed. I didn't even realize it had one.

I'm hoping to get the car back into the shop first week of December. I need to find myself a proper Euro shop though. I'll have to see if my current shop thinks they can help me in the situation.

​​Does anyone have any ideas why nobody can seem to scan my TPMS?
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The most likely explanation is the one you seem not to want to hear: your TPMS batteries are dead or dying. And yes, they tend to go out at around the same time. Four lithium batteries of the same age -- why is it odd that they fail at the same time? Eight years is a normal lifetime for them, but it wouldn't be too unusual for them to go a little sooner. I'd certainly replace them before anything else.

 

That actually IS the answer I want to hear. I would much rather replace them regardless of cost than diagnose and repair damage I may have caused from water exposure. I'm hoping that this is all a weird coincidence.


The trunk issue possibly being related concerns me though.
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Re: soft close - consider this thread, I would check fuse for the trunk motor or check power to the motor. Can you use a multimeter?

are you under warranty? Is there water in the trunk? Timing/heuristics are interesting considering the car wash

https://mbworld.org/forums/c-class-w...air-guide.html

 

A big tire shop like Discount Tire wouldn't charge much to toss in a new sensor. It costs $22 a wheel to mount a tire at my local shop, and one of their sensors is probably $40. So $66 per tire. Have them do one and see if they can get it to connect. If so, then do the rest.

 

Well, this is interesting. I ran out to start the car this morning and when I came back the doors were locked. The vehicle would not respond to keyless entry or pressing the button on the key fob. I ended up having to manually unlock the door using the fob blade.

Not sure if this is related.

No warranty.

I'll have to look into that post in the coming days. Which fuse is for the soft close trunk? All I see listed in the fuse diagram is one for the trunk release...

I think I'll just have my mechanic replace all the wheel sensors when I bring it in a couple weeks. It seems like it probably needs to be done anyway. We'll see what happens...

 

This goes back to the SAM or BCM was affected potentially by water ... you may see more and more gremlins appear soon. Hopefully not.

get a scanner and scan for codes or take it to a dealer and get a proper diagnosis

 

Unfortunately, my shop said they don't have the Mercedes software for their scanner but it's already going there for an alignment and to have the flex disc on the driveshaft replaced on the 6th next month. They are also going to put new TPMS in.

My schedule is jam packed so I won't be able to get it into another shop until January. I really only have time to tinker with this myself a bit on the weekends. I may need to look into buying a scanner that can communicate with the modules...

I'm assuming if a SAM is messed up, it's likely the one in the trunk?

 

consider an autel; I have icarsoft and it'll scan all modules ... buy on Amazon and return it if you aren't satisfied with it, but it may pull some pertinent codes

unclear if it's the trunk module, but my understanding is there is a bcm back there that controls locks and trunk etc - someone else will have more specific info on this

 

$389 black Friday special. My Mercedes isn't the only brand of car I own so the ability to scan other vehicles would be useful.

I need to do a little research but I might go with that one.

 

good choice

are your sunroof drains clean?

 

That's a good question. I will have to look into that.

My scan tool came today. I wasn't able to mess around very much but I did get some codes. Due to limited time I will just share the pictures I took instead of typing it all out.

I had seven faults in total.


Most of these aren't relevant. They were just errors due to things like the head unit not being able to connect to the internet or running low on windshield washer fluid.

TPMS fault: So, over the last few days all the sensors except the left rear has stopped working. I'm guessing the sudden drop in temperature pushed them over the edge and it is only a matter of days before the last one stops working.

Based on what I am seeing here, it doesn't seem there is an issue with the actual module but rather just the sensors need to be replaced, correct?


I know I need to examine the modules mentioned in this thread and see if I can see anything. I'm not exactly sure what I'm looking for or what I should be testing though. I'll have to mess around with it in the coming days. I'm out of time for tonight though...



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You have a fault in your SAM, we discussed this earlier - this could be contributing to your trunk issue

you have a low battery issue with the tpms, and this could be why it's not communicating. You need to replace them anyways, and then you can re scan; however, you still have a code fault with the control unit for the tire pressure monitoring system

issue is why is your SAM giving you a fault code and you have issues with your trunk

you also have false with several control units themselves, you gotta wonder why multiple units are not operating appropriately, try to clear the codes and see if they return after driving normally for a few miles.

i've seen these codes come and go, which has really nothing to do with anything serious. Sometimes it's related to the main battery or a low electrical voltage scenario the trips all of these units simultaneously.

 

I forgot it was the SAM you mentioned.

I meant to go back through this post and scan those modules when I had a moment. I think I know why some of those codes popped.. I tried to pull up one of the apps in the head unit without a subscription just to see what would happen so that must have triggered a code. I also intentionally drained all the windshield washer fluid because there was summer fluid in there so that triggered a code. When I first subscribed to the service for Mbrace, the app couldn't communicate with the car at all so maybe it was why I had a code for the telematics. Customer support did some behind the scenes things and now everything is working fine with the app.

But get this! I just cleared all the codes and now the trunk is working perfectly fine!

I can't tell you about the TPMS issue yet because I have to drive the car but I'm sure they are all going to fault out except the front left one. I'm almost certain they all need to be replaced. That is going to be done this Friday.

I do wonder about some of the codes though, like why the SAM messed up. Maybe it was from my car wash, maybe it wasn't. I guess I will just have to keep driving the car and see what happens.
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Anyway, I'm on my lunch break so I don't have too much time to mess with the vehicle right now but I'm satisfied with this turn of events.

 

I'm glad clearing the codes worked out, that's often a solution for relatively simple problems for these vehicles.

there may have been some type of electrical gremlin associated with the car wash that has now dried up or cleared up somehow. Drive the car for a little bit, 20 to 30 miles and re-scan for codes and if you don't have any codes, you should be good to go. Also have someone do a test of your main battery even though you said it was just replaced, you never know if there is a bad cell and a poorly performing battery even if it was just replaced, can cause some of these electrical gremlins.

and now that you reset the TPms control unit, you may have better luck with your sensors, reporting the actual values of the tire pressure. Also, when you clear the codes, you often will reset the ECU with that scanner and you will also benefit from likely improved throttle performance as the ECU has reset the throttle adaptations and now is gonna learn, potentially more aggressive, driving pattern and give you the feeling that you have a more responsive Engine. For example, and read to the end of this thread.:
https://mbworld.org/forums/w213-amg/...ss-torque.html

another common issue I've seen is bad ground points for the electrical connections, there's a handful of grounding points in the engine bay and likely some in the trunk and these can get corroded or have bad connections, and these can lead to electrical faults, for example
https://mbworld.org/forums/coupe-roa...-stalling.html

https://mbworld.org/forums/e-class-w...ving-them.html

 

@PeterUbers You have certainly given me some reading material to check out this weekend. I'll take a look at it when I have more time.

Unfortunately, the issue is back. As soon as I cleared those codes, I went and tested the trunk and it worked. When I was getting off work I tried to remotely start the car and noticed it was taking longer than usual. I ended up canceling the process and when I went outside I decided to test the trunk. It's no longer working.

Except this time, there are no trouble codes relating to any SAM module. Come to think of it, the first time it was the front SAM module with a fault code relating to a windshield washer fluid. I'm not sure why clearing the codes worked momentarily when there was no fault for the rear SAM.

I tried playing around with the SAMR module and was unable to really accomplish anything. I can pop the trunk and things but I can't really control that latch on its own. When I try, I hear a slight noise in the trunk and nothing happens. But if I do a power release it does open up. I don't know if that tells you anything.

Oh yeah, all the TPMS errors came back. So I'm pretty sure those three sensors are dead. Like I said, I think they were just clinging on to life and once I brought them into Wisconsin winter, they just gave up the ghost. The car was residing in Georgia where it was nice and warm after all.

I also have a head unit error again but it's just for not being able to connect to the internet. I live in the rural area with spotty cell service and I'm guessing whenever it loses connection it triggers a fault code.

Clearing seemingly irrelevant codes did not help this time.

I'm suspecting now I will have to manually test the power latch using the links provided in this thread. Maybe It isn't getting power or sensing when the trunk is touching down.

 

You're back to:
- dying power mechanism for trunk
- dead tpms batteries

 

Well yes, like I said, I'm pretty much certain the TPMS batteries are dead. It was no surprise to get an error message again. I'm 99% sure that when they are replaced Friday the issue will go away.

I just find the trunk issue to be odd though. I don't understand how resetting codes for modules that should have nothing to do with the mechanism would suddenly make it work ever so briefly. I had a fault code for the front SAM, not the rear.

Perhaps this is just one hell of a coincidence that it went bonkers after the car wash and then briefly worked after resetting seemingly unrelated modules.

But yes, I think the next logical step is to diagnose that motor. Maybe I can scrape enough time together this weekend to do some testing as per that linked thread.

I guess these cars are complicated with all the interconnected modules and I'm not exactly an experienced mechanic. I guess I shouldn't expect this all to make sense to me lol.


EDIT: Great, new codes but guess what? I just reset them and the trunk is working again. Let's see if it works when I come out of work.

Here are the codes. I'm terribly sorry they are sideways. My break is ending and I don't have time to fix them.