O.K I will pay $1000 to the person that can figure out the problem with my car with out replacing the ECU. Here are your hints:

After a 5 to 10 minute drive, here is what happens to my car when I shut it off.

1) ESP inop warning when key in position #2
2) Temp flashes back and forth from 40 to 215 degrees when in position #2
3) cooling fan turns on and stays running when in #2
4) If you open the hood you can hear a clunking sound Like if the throttle body flaps are moving open and close fast.
If I put my hand on the intake manifold I can feel the clunking.
5) Car will not start at all keyless start or with key.
6) Seems as if the key is a not programed.
7) When car is in this state not even the MBZ laptop can communicate with cars ECU.
After a while the car will start up and run perfect. Car will run for hours and miles so long as it is not turned off.
GOOD LUCK... OH, AND NEVER A CEL

Is it the car in your sig?

I remember you saying something about driving around with your ground wire loosely connected??

It sounds like you have a gerbil running around your engine messing with things lol

Yes, It is the car in my sig 2007 CLS63
Yes, the groung was loose girbles no sh^t

Have you done an ECU reset yet or are you way past that already?

ECU cold - ROM readable - software / MAP data gets loaded into RAM and computer can use data to run properly. Data stored in ROM will not need to loaded again while running. Once car gets shut down and ECU still hot, data cannot be read anymore due to a damaged ROM; ROM faulty only only when hot . Software needs data from ROM but only gets parts and or faulty code.
Once ECU cools down again ROM readable again.
Electromigration from extreme voltage has caused damage to ROM or parts of datapath without completely destroying it. Soon ECU will completely fry - just a matter of time

In 25 years of engineering (electronic) I have never seen Bad ROM come back to life. I have seen some analog stuff quit working and then come back under the freeze spray but never a Digital ROM. Could be a first though.

Id put a lot of money on the ground being off causing this whole thing.... unfortunately

Can it be repaired? Great call so the ROM or it data path gets hot? why? what makes it get hot or what keeps it cool?

Are you saying that once and if the ROM get hot and shuts down that it should be done? Not recoverable? That's what I thought also.. so we have two going strong. can it be there is a fan in the ECU is it shorted? I do not remember seeing a fan but

It wasn't off, just loose.. but that is what I am trying to pin dowm

what I think is going on in a hopefully easy/basic to understand representative example would be:

There is a wire that got cut. In a cold state the wire is still connecting and electricity can still flow. Once that wire heats up, the heat causes the cut wire to seperate and electricity cannot flow.
( the cut could have happened due to the overvoltage/voltage spike , the wire could represent a trace in the ROM, datapath, etc. etc.)



I have not seen the inside of a ECU yet, but probably it is not cooled by a fan ( I saw the outside of an ECU and it looked like a closed unit - no inlets for air ).

Cooling might help, worth a shot to open up ECU and strap fan to it and see if it becomes more stable. But in the long run electromigration will happen at an increased speed, and eventually the damage will get terminal. If you can really cool the ECU I am sure it will work for a while.
The reason for the heat? Might just be normal operating temperatures that are enough for the data to be corrupted. OR ecessive heat caused by a burned out voltage regulator for the rom, and the ROM receives too high current that cause the ROM to err out.

Can it get repaired? Depends on what really did get damaged. If it is the ROM, maybe changing the ROM only ( with a cpoy of the data stored ) could bring the ECU back to good. If a trace got damaged, this could also get repaired, if the damaged trace is easily accessible. BUT it could be so many other little parts ( like voltage regulators, mosfet etc. etc. ) and I doubt it will be easy to pinpoint it. Might be worth a shot to try another ROM on the ECU; seems like that is what tuners have been doing to your ECU at one point.

I can only advise to open up the ECU and see if you can visibly find anything wrong, something burned out, loose etc.

The facts are:
- the data on ROM is still intact in the cold state.
- the data can be accessed in cold state.
- the data cannot be accessed in warm state.
- the computer itself can work in warm state without a problem (as long as the data from ROM does not need to be accessed again)

Plausible scenarios:
- the rom is damaged, either parts of the memory is unstable or a trace within the ROM is unstable.
or
- the datapath between ROM to processor / ram is damaged and becomes unstable under operating temperatures
OR!
- voltage regulator burned up from voltage spike and supplies ROM with excessive voltage that causes ROM to err out due to heat



EDIT: sorry for all the edits, German is my first language, and I am not a master of the written English...

Makes sense from the issues the OP is having. I am not familiar with MB's ECUs but are there such things as a batch file which commands are being disrupt (I say disrupt and I explain below) so no code/command transfer is being correlated and or interpreted/passed as functional command data.

I guess a person would need to understand where the transfer is taking place (ROM/RAM)... is there a go between as a command/bus process when dealing between ROM/RAM… as you stated.

Speaking of bus/transfer rate at the ECU and or wires constantly relaying energy/heat... this might have caused a weak connection from rate/heat over little time maybe? Heat expanding a wire(s) and due to this the wires at your ECU have expanded a bit allowing the thinning (slight stretching of the coating off the wire) and this so called stretching off the wire is allowing transfer to jump wire and conflict what commands are being pushed between such wires?

Or maybe the car has a female type ECU… causing the whole car to go raging into off the wall sequence of events from one little simple tiny thing that the ECU will never forget… and just this tiny little glitch allows the entire car’s surroundings (total make-up) to go haywire for a short time but then after the cool down has occurred… it goes back to normal for a while.

I'm not a tuner, but just by the simple fact that it does not start at all when you attempt to go keyless. I suspect there is a defect or short or even a surge in the keyless' radio remote reciever which is causing the two (key and keyless system) to work agianst each other. There has to be a keyless reciever/module or something that communicates with the ECU, I think you should start there. The clicking and throttle opening makes sense, think about it, my car makes similar noises when I put the key in and turn to#2, I here a buzz and a couple of clicks, almost like an auto choke or prime is taking place before you hear the starter turn.

Great point! Makes perfect sense... maybe the negative batter cable played into this as well... caused failure of the receiver and it is probably going to be one of those $19.99 part replacement that does the trick.

I'll tame the cash, just because I can get a new ECU for under $1k.

I don't know crap about electronics, but I know the MB ECUs were designed to run on the hot engine and there is no fan. Heck, the C350 ECU is literally on top of the motor.

If this were anyone else but Rick, I'd be in sceptic mode, but we are good friends and I know he would not make a big deal of something if he did not feel the need to. Also, I know for a fact that he could care less about the $1k for a new ECU.

My view:
Since it is a given that this ecu has been "tuned" by removing the ROM, could it not be plausible that the ECU was pre-dispositioned for failure?

Had your tuner not already ended your chances of any warranty by NOT sealing the ECU? Had the ECU gone in "looking" normal, would it have been warrantied?

For the best testing, I say we pull the roms off and see if they are good.

Keyless go isn't the only issue. Even if it costs $19.99, we still have major issues. Note, they all are centered in the ECU. Fix the commonalities and you may not have to replace all the $19.99 parts.

BTW, what electrical MB part runs $19.99?

from another bad ECU thread:

That one is a 55K ECU, but again one that had many ROM tunes...

LOL.. it was a figure of speach... speaking in terms of or comparison there of, at times a major problem sometimes is just a small simple part fix.

Hey, Looks like we are all having fun with this one Oh and wait no bickering This is how I remamber this board being Oh what fun On the 63's there is no removing of any parts of the ECU to tune. I have stood right next to the tunner many times as we down loaded the new files (tune.) It is very safe if you know what you are doing. I would like to say once and for all " I DO NOT PUT THE BLAME ON ANYONE FOR THIS PROBLEM". Every tuner and Vendor here does their best 100% to make sure we all have the best possible products on the market. I own a car dealership and know that " SH*T HAPPENS" like it or not it is part of doing Business. It's what we do to clean up the sh^t that sets up apart from the rest.. NOW, WHO AM I GOING TO SEND THE $1000 TO We have some very good ideas and I will open the ECU up to see what I can see..

post some high res pics of the internals if you get a chance. Also check with your nose if you can smell anything burned

Don't open up the ECU, you are going to create bigger issues. It does not sound like that is where the issue is rooted.

I feel the same way but I must at least see if there is anything to see that may be staring me in the face. I took the day off work today to play with the car. First day off in 110 days. I will hope to see or find something.. Will report back later today.

The clicking noises heard under the hood are the throttle plates opening and closing in a self test. The esp light (triangle) is a normal light when in position 2, engine off. I think we need an image of the instrument cluster. Is the SDS able to communicate normally without this acting up? Is the ME the only module not recognized, or does the short test hang up on the ME? How does the ME smell if you have it unplugged and in your hands while it is acting up? Burned, or like ozone? Ozone has a pretty distinct smell, like an electrical smell. I know that will have some of you laughing.

Nick

I agree, don't open it up, unless it has screws, then I would!