watermelon

Hi all,
I have a 2000 E320 Wagon. The first EIS went out at Year 2. The second EIS died about a month ago (4 y.o.). Basically, in both cases, went to the car and the key wouldn't turn. Replacing the EIS seemed to do the trick each time, although this last time, they could only get 1 out of 3 remotes to work again (wallet reserve key seems to work still).

Like a lot of people, I have had the typical abundance of small electrical problems/warning lights going off and quite a few things needing to be replaced - at least more than I like compared to competitor car.

Also, during this last EIS failure, the cooling fan wouldn't start - needed to be "reprogrammed" to get going.

My question is: Is it possible that all my problems could be related? My understanding is that the EIS is central to CAN interfaces and execution of diagnostics.

Is it possible that something electrical/electronic is causing false positives along the CANs and somehow taxing the EIS? And because of this, is immune to normal diagnostics performed through the EIS?

What should I try to get the dealership to test individually in isolation, or to do in general? could it be something with the CANs, voltages etc.?

TIA
W.

TECHR46

did you have work done at the dealership? You are correct, the EIS is "king" of the CAN. IF any keys are not working, they probably need to get 'learned' to the vehicle again.

SUNILP

King until the advent of the Central Gateway in later cars such as the 06 SL.

MBTech21

In answer to your question- it is indeed the master of the Can 'B' (interior) and also acts as a gateway between the 'B' abd Can 'C' (engine/driveline) can. So it is hooked to both and it is possible that a corroded Can signal could cause issues over time (or you just had bad luck with EIS's!). The weird thing is the cooling fan- it is controlled via the ME-SFI (engine) control module, so, I have to think they had some coding wrong in the EIS that really made the car retarded (ie: it doesn;t know how hot it is, or what kind of engine it has,etc).
All the keys should work with the new EIS, if they worked before. Did they have them all when they did the job? This is usually not the case, so that may explain that.
As far as checking the CAN- this would be a corroded or corrupt signal, not a failure, or the CAN would be inoperative all the time, so the only way to really check is with scope (both Can systems)- the 'C' can is much faster, so has to be a pretty fast scope, with a cursor option to get good readings. I'd like to think that all MB dealers have at least one guy with a scope and the ability to use it, that could check out both systems, and if they look OK, put your mind at rest in a bout an hr, but sadly, I know thats not true. So, if you run it by them (try to talk to the foreman, not an advisor), and he seems at all shakey on what you are talking about, move on..I didn;t notice what part of the country you are in, maybe I can point you to a guy that could do this.

Hope this helps..

watermelon

Thanks all. This is very helpful b/c it does confirm some of the things I suspect and what I've been trying to convey to technicians.

I do get all my work done at a dealership. I am in the L.A./SoCal area.

Tech21 - yes, as I had gone through this before, I gave all my keys when I delivered the car, except the wallet key which I had forgotten I had. Oddly, the wallet key works still.

By "scope", you mean oscilloscope? Is there a specific procedure name for that analysis? I have been working with a senior technician who is trying to research the problem, and had mentioned that very casually before. I will try again but a name might make it more clear to him.

Since you mention the ME-SFI - a few days after I picked up my car after EIS replacement, the Check Engine light went off - they said it was a bad Mass Air Flow Sensor (they replaced it).

Could this be related? I didn't want them to work on it at first in case there could be a link to/troubleshooting with the EIS problems - but they told me they were two separate systems. But is it possible there have been nothing wrong with my components, but the monitoring/warning system of my car is screwed up b/c of something related with the EIS/CAN? Could a faulty/corroded CAN screw up the Sensor?

Also, this weekend - basically within just a couple hundred miles after EIS replacement, and just after Sensor replacement I've also seen this:

a) Rear Window Wiper and Sprayer not responding to dash button at all.

b) During the day, when the car is turned on for the first time, the
Dash Thermometer sometimes reads 100-130 F degrees then slowly drops
35-65 degrees (over about 5-10 minutes) to what is probably the
correct temperature. This happened near the beach in the late
morning, so I don't think the temperature under the car could be
anywhere near 100 degrees.

c) Don't know if this is abnormal, but the following are
inconsistencies that I've just noticed that seem to be in conflict
with the owner's manual:
- -We have our Key Remotes set to "Selective", i.e. one push unlocks
the driver's door, two pushes unlocks all doors. Central Locking is
set to Automatic, linked to the car's speed. When we exit the car,
most of the time opening the driver's door unlocks ALL doors
(sometimes, however, the other doors don't unlock). According to the
manual, all doors opening with the driver's door should only happen if
the Key Remote is set to "Global". Is this correct behavior?

Thanks so much for your help.

mleskovar

[QUOTE=watermelon;1861952]When we exit the car,
most of the time opening the driver's door unlocks ALL doors
(sometimes, however, the other doors don't unlock).... Is this correct behavior?QUOTE]

If you unlock the car with a single push of the button then the other doors will not unlock when exiting through the driver's door. If you push the button twice to unlock all doors when entering the car, then all the doors will unlock when exiting.

MBTech21

Yes it is an osilliscope I am refering to, there isn't any real published tests for it, but any of us skilled with one, know exactly what a good pattern looks like- I have some stored ones in my scope, I will try to upload them Moday for you (scope is at work-obviously!!).
However- the one thing you said hits home the most- with the rear wiper not working- the car thinks it's a sedan (hence no rear wiper)- this will also pile up a bunch of other things (it sees siganls it doesn't think it should and then guesses at what to do).
This is very common- a lot of guys get this wrong when coding- W is sedan, S is wagon, and it asks you that when you code it, so if you are thinking in english, instead of german, you would think S is sedan, W is wagon..
Hope this helps.

watermelon

Thanks again Tech21.

I am pretty sure the rear wiper worked (got used) some time after the EIS replacement but before the Mass Air Flow Sensor replacement - it was only a matter of a week to ten days, so maybe I'm wrong...

Nevertheless, would replacing/testing the Mass Air Flow Sensor require the technician to make adjustments/recode things that would provide the opportunity for the error you describe?

You mentioned before that the C CAN requires a "very fast scope... with cursor options" Does that type of scope have a name, model number, or threshold designation that a technician would readily recognize? Anybody you know in Los Angeles or SoCal Regional?

Also, I wanted to get your opinion on how "going to Regional" is construed by the dealership guys. I have really been trying to preserve the local relationship - have not reported to Regional, and have been very patient with the high-level technical person at the dealership. He was responsive about the Air Mass Flow Sensor, but it has been over a month since he knew about and promised to take action on the EIS/key failures. He said he needed to "research it". I contacted him at the beginning of last week and followed up by phone, but have not heard from him at all.

What are the politics of the dealership asking for Regional help - is it something he wouldn't want to do (e.g. is it considered a shortcoming and ding against the dealership)? Do they prefer or care that the customer initiate it? Or is it considered a slight by the customer?

I left him a message that I would like a response of some kind by Tuesday of next week (i.e. his proposed next steps, or lack thereof) - would it be acceptable for me to contact Regional after that? From my understanding, he is the head technical person at my dealership, so I don't know where else to go locally.

Thanks for your input.