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The new ECU came VIN-coded (actually serial number coded,.. VIN are based on serial number) from the Mercedes warehouse (Dealership does not do this coding)). Officially ECU can be VIN-coded only once (virgin ECU married to VIN). Once the new ECU is installed onto the car, it still needs to be SCN (Software Calibration Number) coded. All 2003 and newer Mercedes car have ECU requiring SCN. The SCN is a 16 alpha-numeric string,.. it basically enables the ECU to communicate to the other computers in the car like the Transmission Control Unit, EIS, body control unit, etc,... The SCN is available via secure network from Germany,... thus nobody actually see the 16 digit SCN itself,... if they did, they can steal your car!
Careful about buying reconditioned ECU online,... some claim that they will be shipped to you fully VIN-coded and ready for plug and play. But it still needs SCN coding. My understanding is that the ECU must be installed in the car before SCN coding can take place,... and SCN coding needs a live connection to a MB computer in Germany,... top security,... otherwise anyone who can read your VIN code from you windshield can get a programed ECU for your car and thus steal your car!
The only way a used ECU can work on your car is if the chip storing the VIN-Serial number and SCN code are replaced with the chip from your old ECU,... that way the used ECU will have your VIN-Serial number and SCN code and will be able to work on your car. Hmmm,... same methodology as the old key to new Chrome key chip transfer. To do this ECU rebuilders require your old ECU,... and if you have to mail it to them,.. lets hope it doesn't get lost!
Of course, the Mercedes-Benz Dealership can do SCN coding. In the USA, because of their Right To Repair laws, some Mercedes Indy and ECU experts can do SCN coding (they need to connect to a Mercedes-Benz computer in Germany). My Mercedes Indy in Canada goes through a Mercedes ECU expert in California who can connect to the MB computer in Germany.
While doing my research,... I know ECU damage are quite rare. The parts manager at my local MB dealership (one of the larger of 7 dealership in Toronto area) mentions in an entire year, they only see about 1 or 2 orders for ECU. Even my Mercedes Indy (the best Mercedes Indy in Toronto,... Aidan & Charlie McNally Auto - 15 bays with 8 mechanics) only sees about 1 ECU replacement a year.
If you suspect your ECU is damaged,... you need to hook it up to STAR to see status of ECU,... inspect all wiring, main wiring harness, CAN bus, fuse, relays, etc,.... ECU are very well protected with fuse, relays and breakers,... but a short in main wiring harness can fry ECU. If your ECU is non-communicative (dead),... it will not send signal to front radiator cooling fan,... front radiator cooling fan go into its default mode and spin in high mode like a turbine engine,... it assumes worst case that the engine is overheating. Making a call on a dead ECU is very tough to do,... and since ECU are generally expensive, that call better be 100% correct. The only way to be 100% correct,... would be to plug in another ECU for that engine model,... the other ECU will not be able to start your car since VIN and SCN are different,... but the other ECU will be communicative (have status on STAR),... and thus front radiator fan will not be spinning in high mode since it gets a signal from ECU.
If an ECU is damaged, common ECU faults are blown output stages (no power to fuel injectors) which cost about $100 to fix. Damaged EEPROM for faulty ECU programing (bag ECU tuning) usually cost about $200-400 to fix. Immobilzer are in ECU. Any ECU (old or new) would need to be VIN-coded and SCN coded to the car which usually cost about $200.
New ECU are only available via Mercedes-Benz dealerships. Thus, RMEuropean and other non-MB places would NOT carry them. GetMercedesParts (really an MB dealership) sell them for $1365 (25% of the list price of $1820). The really shocking part is that the Canadian Mercedes Benz dealership actually sell these ECU for less than the American Mercedes Benz dealership! It is usually the other way around where the Canadian MB dealership charge about 50% to double what the American MB dealership does (ie Car batteries). At the Canadian MB dealership, the ECU cost $1060,... and with the Mercedes-Benz Canada Loyalty Circle program I got 20% off so the new ECU costed me $848 plus tax,... well, there goes my mod money for a while,... the mod money, I've been saving from doing some of my own maintenance thanks to the DIY threads here.
Hey, thanks for the detailed response and the pics. I've had my car back two days and all is fine. Hopefully it was just a bad connection. ECU connectors do not appear oily, maybe just oxidized and required a clean and reseat. I work on Flight Simulators and we regularly face this type of thing where a re-seat fixes the problem. Fingers crossed all OK now. Regards Greg
Are you in a very dusty part of Dubai? The ECU plug are generally pretty well sealed,.. along the edge, there is a rubber-silicone gasket. The oil can find its way in via the main wiring harness,... if there's any oil in the main wiring harness, just spray some CRC QD Electronic Cleaner there,... but avoid any part with tape, it will eat away at the adhedsive.
Some dielectric grease at the connector might help,... if theres an ongoing issue with oil, water, dust, oxidation, etc,.... but you should only use very little dielectric grease,.. just enought to put a very thin layer on the male tips of the ECU connector plugs. Personally,... if it works fine now, don't mess with it. If it needs to be re-seated again,.. try appling a little bit of dielectric grease.
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort (What the heck, it gets 38 mpg!)
Just revisting this thread...in the beginning, you said you owed me one? Not sure...
so EH, nice solder job, arrrgh. Did you try resoldering?
Of course you have to be very careful, all computer PCB's are multi layer, too much heat fuses the layers, and you have a nice piece of junk for your collection. A guy in Greece managed to replace a 4 sided chip in his SAM without frying it...somewhere around here.
So, did you do the ECU yourself or have a dealer do it? Of course it requires SDS.
PS, how cute, you posted Bob and Doug video's.
I used to have their album on cassette....but the movie was the funniest thing they ever did.
Silly, but I laughed my **** off, eh!! I'll have to tell you of my fun at Pickering someday, helping them set up a control system.
My front fuse box seems to keep coming open by itself, something to keep an eye on.
Last edited by C230 Sport Coup; 11-06-2012 at 03:54 PM.
If you examine the photos, you`ll notice the solder joints are rather weak, in that the component leg are just soldered onto the top of the solder point,.. instead of having a small blob of solder build up and enclose it. The thing is this wasn`t done as human error,... its robotic soldering so there should be many ECU circuit board out there with weak soldering jobs.
Resoldering would have been an option when the problem (stalling and non-start with fan spinning in high mode) was intermediate,... caused by a crystal oscillator feet that came loose from the circuit board,... If I had found this cause early enough, resoldering would have been my best option since it`s a rather simple DIY,... taking the case off the ECU would have been the toughest part. And this would be my suggested fix for the next person that experiences the same problems I did on an intermediate basis.
My problem eventually became a permanent non-start condition,... and I believe that was caused by both feet of the crystal oscillator becoming loose from the circuit board,... then crystal oscillator bouncing around in the ECU, keep in mind crystal oscillator has a metal body that will cause shorts and ground out within the ECU, the ECU became non-communicative (dead) on STAR,... and without the expertise to thoroughly test my old ECU under all the possible states and conditions,... I can not trust my old ECU,... the best option was to buy a new ECU from the parts department at a local Mercedes-Benz dealer. My Mercedes Indy (McNally Auto) that did the initial diagnosis installed the new ECU and used a Mercedes ECU expert in California for the SCN coding.
Why does your front fuse box open by itself?,... the front SAM, relays and fuses are in there,... it should be water tight,... otherwise, its very expensive to repair,... make sure the drainage is good in that area. Check the lid of your front fuse box,... is the plastic lid or metal clips or rubber gasket seal broken,.... Todd, I have an extra lid with good clip (it only has one out of the two clips) and rubber seals that you can have for free if you need it,... you just cover shipping.
SunnyRay...great write-up. Because this - as you point out - happens so rarely, there's not a great deal of information available.
My C32 AMG is sitting at a credible merc dealership in Sydney. After 7 hours in front of a mercedes technician they still can't pin the cause. They can't get it out of limp mode. Had the "ESP - Visit Workshop", shuddering, engine shut off etc. Trouble is, as you so rightly point out, they are correctly trying everything else...wiring harness NO, throttle body NO, SAMs, Relays NO etc before arriving at the ECM. That would cost $8,000 aussie dollars which is about $8,300 U.S. Quite an amount for anyone. Faced with this I was very glad to have chanced across your write-up as it at least gives me some knowledge with which to communicate with the dealer. The service manager already primed me with the fact that the ECM is coded to the car. Only last month the Fuel Pump went and I no choice but to shell out $4,677 for the luxury of a new one. That's after having spent $1,000 at a local custom car shop to diagnose the problem (long crank time > non start) by changing the CPS and then spark plugs all round. So this ageing car has cost me far too much. My '08 is a dream. The '02 is past it. I'm bracing myself for that dreaded call to come. "Sir, we have narrowed it down to the ECM/ECU main computer. That will be $8,000 please". Of course, I shall try and track down a virgin unit from the U.S and try to keep the cost down...
...At least I now have several other avenues to try before then. I really appreciate the time you've taken to elaborate on your own experience, and to kindly provide your research findings. Bravo to you Sir.
Last edited by When I Say Go; 11-08-2012 at 06:09 AM.
Reason: poor grammar & trying to get a decent emoticon
When I Say Go,.... Limp mode is *usually* a sign of transmission problems. Limp mode as in, the car is still drivable,... it stays in low gear and limited to low speed driving.
I assume transmission issues have been checked,... like transmission oil level,... any leaks at transmission pilot bushing adapter,... oil at TCU,...
When your car goes into limp mode, it might trigger ESP Visit Workshop message,.... but that would not account for the engine shuddering or stalling,...
With ECU problems,... especially if the ECU causes a stall or non-start, the ECU becomes non-communicative and when front radiator cooling fan does not get a signal from ECU it goes into its default mode of spinning in high mode, like a turbine engine (it assumes the worst case scenario, that engine is overheating),.. trust me, you'll notice it! It would be really loud,... louder than when the engine is running!
Some questions:
- Is your front radiator fan spinning in high mode,....
- does the Coolant Visit Workshop message comes on the dash,....
- when hooked up onto SDS (STAR) is your ECU communicative,... is there a status,....
- has your ECU ever been tuned or modified,....
- what is the mileage and year of your car,...
- do you regularly change (partial) transmission oil every 60,000km
- are ECU and TCU connnectors clean of oil
- has CAN-bus also been checked
Based on the information so far,... I would say its not your ECU,... well, at least the ECU isn`t completely dead and need to be replaced,... the ECU seems to still be communicative (since you didn`t mention any issue with front radiator fan spinning in high mode),.... if ECU, it might be something relatively fixable like ECU has problem with blown output stages (no power to fuel injectors) which cost about $100 to fix,....
I`d be asking a lot of questions if they were to suggest a ECU replacement,... a lot of times MB dealerships would rather just replace the part than to do a simple fix like just clean it properly,...
Your issue sounds more like a transmission issue,... especially if the car is high mileage without proper transmission oil changes (as in MBUSA filled for life crap,.. yes, you`re in ROW). Then it might be a conductor plate issue,... that might explain the engine shuddering and stall. But an MB tech should be able to diagnose relatively easily,...
Second guess, would be a relay in your front SAM,.... or damage cable under the battery,... there's no water damage in those compartment, right,....
Did you get any error codes on OBD2 or STAR prior to changing CPS,.... if so did you do a CPS recalibration,... search under my id for *CPS recalibration* to see how its done.
You mentioned quite a bit of recent work,... why were they done,... and have they been checked,.... make sure to mention the recent work to your MB tech,... just in case its related to your current issues
Thanks for your inputs. Your logic sounds spot on. The ECU can't be dead, just impaired, or actually doing it's job and limiting any further damage. The Transmission...I've had no issues with it, and in March 2011 it had a Transmission Service during a Service A. That was 18,000 miles back. I note that the transmission mount was replaced at the same time.
In direct reply to your questions:
- Is your front radiator fan spinning in high mode,.... NO
- does the Coolant Visit Workshop message comes on the dash,.... NO
- when hooked up onto SDS (STAR) is your ECU communicative,... is there a status,....I BELIEVE SO. MB guys tell me that it is communicating. Must be to get some codes.
- has your ECU ever been tuned or modified,....NO. It's STOCK.
- what is the mileage and year of your car,...92,000 Miles / 148,000 km
- do you regularly change (partial) transmission oil every 60,000km YES. Had a Transmission Service during service A at a MB Dealer in Mar 2011. Regularly change the Engine Oil and SC Oil (with the proper Mobil Jet Oil / 254)
- are ECU and TCU connnectors clean of oil I BELIEVE SO. MB techs should have checked that.
- has CAN-bus also been checked NOT SURE, I think MB are checking that. Backtracking attempting to find cause.
Yes, the car definitely shuddered. Jerked. Stop-start-stop-start, but engine still running. No throttle input. Like riding on a camel that can't make it's mind up! It drove a couple of minutes later for about a mile (with no shudder) until I pulled over into a suitable park. Was definitely in limp mode as throttle input limited. I'm sure the engine switched off itself at that point.
I hadn't done a CPS calibration, so that may be a cause?! CPS was installed about 500 miles ago and no issue from that - nothing to report out of the ordinary. The check engine light came on after the ESP warning. I guess they all light up.
Last thing on the car to go bad was the Fuel Pump which was apparently stuck on at full capacity. I wondered why she was running so sweet But that was fixed at great expense.
The only mods made to the car are cosmetic.
Curiously MB told me that the car has a V8 throttle body on it, not the V6 version. Very odd. I know the TB is 74mm (same as stock E55 one). Can't find any record of that having been changed, or indeed any issue with it. Not related to this though as MB connected another TB to check and removed that as a possible cause (of this current issue). There diagnosis originally pointed to the throttle body. They've checked the pedal sensor (not that) and the wiring harness (not that). I think that's why they're looking at the ECM. Service Manager said they'd have to chat to MB Worldwide to get to the cause. They just can't get it out of Limp Mode.
I think the Transmission, despite the fairly recent service is very possible given the symptoms. I guess if the CPS was misaligned, I'd get some form of shudder, but there would be a corresponding warning/CEL surely.
Once again, thanks for your help!
Last edited by When I Say Go; 11-08-2012 at 06:31 PM.
Reason: formatting
Ok,... 722.6 transmission is regularly serviced unlike those in USA,... When properly serviced these transmission should last a million miles!,... And ECU are quite robust with very very low failure rate,...
It could be something as simple as oil in one of the electrical plugs causing bad reading,.... or a broken or loose vacuum-air hose,...
Because you just got the CPS done,... and keep in mind, I do NOT know how to change a CPS on your C32 AMG engine,.. but I have changed my CPS on my M271 engine with 722.6 transmission,.... that said, when changing the CPS, I would have to remove the air filter housing and MAF housing,... and there are a few hoses including a vacuum hose, rubber hose from engine intake to MAF tube, etc,.... anyways, if any of these hose are not placed back properly or become damaged,... that could account for the engine shudder, jerk and stalling problem. I doubt it would cause limp mode,... but unfortunately, I am not that familiar with your C32 AMG engine,.... I really wish I was!
I would not worry about the ESP warning,... it likely got triggered because the engine shuddered or jerked while car was in motion,.... You could resynch ESP by turning steering wheel all the way in one direction and then the other,... do it a couple of times....
If you are concerned about throttle body,.... try a ECU reset,... to reset throttle and adaptive transmission settings back to factory specs,...
ECU reset (with car in PARK):
- Key in to position 2 - do NOT start the car
- Press Gas all the way down (kickdown mode) and hold for 5 seconds
- Turn Key to Off position (do NOT take key out - still pressing gas pedal down)
- Release gas pedal
- Wait 30 seconds to 2 minutes
- Start car as usual
ECU reset is good if you do lots of city driving in congestion and thus your adaptive transmission adapts to GrandMa driving style,.... Do it once every 500-1000km,.... its like getting a tune-up
BTW,.... I bet your MB tech doesn't know about this ECU reset trick,...
Thanks so much for your help. I am using an abridged version of this dialogue to discuss with the Service Foreman...point him in the right direction hehe. I will get them to supply me with the codes they've pulled.
I will definitely get them to check the hoses/connections to the MAF. I know they found some vacuum leaks.
At least now I maintain some Hope!
Your help has been invaluable. I'll be sure to post the outcome.
Btw, Toronto is a beautiful city, so clean. I remember Pearson Airport as a modern masterpiece of architecture! Spent a week with work in Mississauga a few years back and loved my time there. Got a few days to have a look around. Remember the fines for excessive speeding on your freeways were massive. Not that I incurred one!
Last edited by When I Say Go; 11-10-2012 at 04:10 AM.
Reason: missed point 2
I have a 2004 CL500 whats the best way to get the ECM fixed
Basiclly whats going on is I crashed my CL500 and after everything was fixed. I noticed when I start the car my fan turns on full speed all the time none stop. I had 3 mechanics look at it. They said its the ECM.
What they said the fan got shorted and effected the ECM, now they are saying only way to fix is buying a new one. Dealer wont program a used one only a brand new.
I found a rebuild website for my excact item number but they want like $800 for it and they claim they can program so I can plug and play.
What do you think is the best way to fix this issue?
Cars runs great only issue is the Fan is always on full speed. Nothing to do with coolant sensors all are good.
Did your mechanic test the fan and the fan control module??? I would really suspect the fan or fan control module? How did your mechanic test it?
If ECU fails,... then the fan control modules does NOT get a signal from ECU,... then the fan control module causes the fan to spin in high mode like a turbine engine - that's the default! It does that because it assumes the worst, that the engine is overheating,... Now if, your mechanics are thinking ECU is failing,... then why does car start, run and does not stall????
How much is the new ECU at Stealership? Generally, $1000 to $3000. If it's lower of the range,... why rebuild for $800???
Read the thread,... Dealer can NOT program a used one,... nobody can,... ECU are Serial# (VIN) coded,... and then SCN coded. Once ECU is Serial# (VIN) coded, it can NOT be married to another car. Translation used ECU will not work on your car regardless of who programs or rebuild it.
The only way for a ECU rebuilder to get a used ECU to work on your car is they need to switch the chip that stores the Serial# (VIN) code,... thus, you will need to drop off or mail your old ECU,.... and if it gets lost, well,..... and even if all this is done successfully,... you better make sure its also SCN coded properly.
My suggestion,... get your mechanic to plug in another ECU from another CLS onto your car,... your car won't start! But if the fan still spins on high mode, you'll know it's NOT the ECU at fault. If the fan, does NOT spin in high mode, then it's likely ECU.
Your mechanic also needs to check the wiring between ECU and fan control module,...
I own a 2003 C230 Coupe with 80,000 miles. While the car is running the fans are always on high.
With our test tool (Launch) we attempted to vary the fan speed. The tool said the fans were changing speed but they (Fans) physically never changed speed.
We were able to successfully test other systems in the C230 so the ECU can be communicated with.
The car runs and drives perfectly. (It has never stalled)
I am relatively sure it is not the fan control module because the fans shut off when the car is off. When fan controllers typically fail the fans usually keep running even when the car is shut off. (Killing the battery)
I have only found ONE company (Mercedesecm.com) that claims to fix ECM's. I do not know of any others and information is very hard to find because some people refer to the ECM as the ME & some call it the ECU.
Basically what I am looking for are options and information.
1. Are there any other companies that can repair my ECM or do the necessary SCN coding on a good used ECM?
2. Are there any other resources (Websites, Links Etc) that explain how to diagnose, clean or fix etc the ECM?
- Is your front radiator fan spinning in high mode: YES
- does the Coolant Visit Workshop message comes on the dash: NO
- when hooked up onto SDS (STAR) is your ECU communicative,... is there a status: YES
- has your ECU ever been tuned or modified: NO
- what is the mileage and year of your car: 2003, 80K
- do you regularly change (partial) transmission oil every 60,000km: YES
- are ECU and TCU connectors clean of oil: NO
- has CAN-bus also been checked : YES
If you live in the LA area you are in luck. There is a company GNN Motors that can recode and marry a used ECM (ME) to your Mercedes. http://gnnmotors.com/scn-coding.html. They can not preform any of these services without the car present.
If anyone knows of a vendor (outside of the Mercedes dealership) that can recode and marry a used ECM (ME) please post the link here. (I have no interest in spending over $1000 for a new ECM and another several hundred dollars having the dealer code the ECM)
Thank you in advance for all your any advice and suggestions.
Your car starts and run without stalling,.... So why would you even think ecu is faulty?
If ecu dies then there is no signal to front radiator fan,..... Front radiator fan spins in high mode by default. But your car is still running, so you ecu must be good!
Since you have oil at wires and ecu plugs,.... Clean plugs with crc electrical cleaner,......
Also examine plug for front radiator fan for oil and corrosion.
Also, try changing out your coolant temperature sensor,... Mercedes-Benz part# A000-905-07-00,... SIMPLE Do it yourself,... $20 part
Last edited by SunnyRayToronto; 04-04-2013 at 12:32 AM.
Dealer says my ECM is dead. I am skeptical. My van, 2008 sprinter 2500) was running fine then just quit - I rolled to the side of the road and checked a few things like engine heat, oil, ....All seemed normal (I'm a mechanic) so I tried to start the vehicle again. It cranked started sputtering then started and idle smoothly for about 3 to 4 seconds. I tried again- no start. I waited about 5 minutes and tried again. Started sputtering and started - ran smooth for 3-4 seconds and died. My brain says fuel related problem so I call tow truck and haul this to the dealer. $800 later Dealer says that engineer from tech line says ECM gone. I asked the dealer to change the fuel filter and do a volume test. Volume is in spec including rail pressure to injectors. What the dealer experiences when they try to start the engine is it sputters when they try to start it and eventually come to life but runs rough then quits. To me, the fact that it tries to start indicates functioning control but perhaps a failure on the input or output sides of things. Is this something anyone has heard of before?
What does the STAR Diagnostic report says? You paid $800 for tow and Mercedes-Benz STAR Diagnostic System report,... so what does it say? You paid for it, it's yours! Get it from the dealer and report codes here.
Like I said, ECU failure is very rare,... very very rare!
When your MB Sprinter (BTW, wrong forum, but you probably won't find a ECU failure thread on Sprinter forum because ECU failure is so very very rare!),... anyways, when your MB Sprinter stalled or failed to start does the front radiator fan starts spinning in high mode like a jet turbine engine? Very, very loud!!! If so, then that's a symptom of ECU failure since when ECU fails, it can't send signal to front radiator fan. When front radiator fan doesn't get signal from ECU, it starts spinning in high mode as it's default - it assumes the worst, that engine is overheating or on fire.
Blown output stage on ECU are common ECU failures and generally inexpensive to fix at ECU shop. If your ECU is really dead, then getting used ECU and transplanting your EPROM chip (that stores VIN-code and SCN-code) should be way cheaper than buying new ECU that needs to be SCN-coded.
Also, check CPS. You said Sprinter was running fine and then stalled,.... sounds like common CPS problem when it gets too hot. Replace with OEM Crank Position Sensor.
What's mileage on your Sprinter? If high mileage, sputtering could be from clogged injectors - use Techron.
Hello, i have a mercedes w140 S500 from 1997 and after i change the engine with another engine from 1996, my car won.t speed up after 3500 rotations. I mention that Ecu is from 1997. Any ideea?
How to Open ECU in c230 to check for oil (2005 kompressor)
Originally Posted by SunnyRayToronto
its relatively simple to fix (VS the cost of new ECU or ECU repair, you really have nothing to lose),.. take out the ECU via MAF DIY style to remove airbox housing to which ECU is attached,... then carefully break open watertight rubber seal of ECU (this will take some time),.... examine solder points of crystal oscillator,... resolder crystal oscillator to circuit board. Reseal ECU with good quality automotive seal.
Mercedes says the ECU in my 2005 C230 is contaminated with oil and the car is not worth fixing despite only 50,000 miles on replacement engine. I question their assessment and I'd like to confirm whether there is really oil in the ECU before considering to fix the root cause (leaking camshaft solenoids / isolation cables).
I'm wondering how you opened your ECU. Your photos look like the lid was damaged. Was that your ECU or other photos? Any tips to opening the ECU and resealing would be much appreciated.
My old ECU was toast,... so it was dremel open to figure out what was broken inside,.... and those water-tight seal are basically like epoxy glue. So if you want to reuse your ECU then dremel and pry apart at the water-tight seal and then re-seal.
But in your case, I seriously doubt you need to even open your ECU,.... they found oil on your ECU connector,... so you use CRC QD (Quick Dry) Electronic Cleaner to clean the oil,.. and spray the hell out of it! If oil is actually getting into your ECU (which I seriously doubt), then the oil is getting in via the plug connector - so spray the hell out of it and the CRC QD Electronic Cleaner will also be getting into your ECU where it'll clean the oil that's in your ECU! Which I seriously doubt is even there,....
MB-STEALERship will make charge an arm and leg to change out ECU,.... for them it's free money! Usually not necessary in these case. You have isolation pigtails cables,... so why oil even getting to the main harness,.... and even if it gets to main harness there's thread here on how to soak it to get rid of all the oil,.....
BTW, your Mercedes is over 10 years old now,.. why keep bending over at Mercedes-STEALERship,... get a Merecedes Indy
Thanks SunnyRayToronto. I had troubles finding an independent mechanic that was able to work on Mercedes.
- One over-filled the oil on my first engine and I abandoned him once that engine rattled to death with timing chain / guide / valve-piston contact issues.
- The mechanic that swapped the engine didn't bother to tell me that one of A/C pump bolts was missing when he replaced the first engine.
- Another that "specialized in Mercedes" didn't advise me that the solenoids hadn't been isolated with the fix cables,
- The fourth didn't torque down the new serpentine belt tensionner correctly and it dropped out one day and ripped open the air box in front of the belt.
So I went to MB stealership as a last hope due to rough idle, often almost stalling while decelerating at stop signs, and occassional warnings of "Check Battery/Alternator" while decelerating at stop signs.
I brought it into MB and they charged me $500 to tell me the car wasn't worth fixing. I then had to ask them what the appropriate idle RPM was? They said 800 and I said the tach showed 600. Then they offered to increase the RPM by 50 (the max permitted by their programming system).
I cleaned solenoid connectors and ECU connectors with CRC QD and it's running really well now except for occasional battery/alternator warning. I'm just a bit spooked which is why I want to check the ECU for oil. I suppose it wouldn't hurt to just fill the connector with CRC QD as you suggest. What do you think of the following approach for a Bosch ECU?
I realize that the c230 ECU doesn't have any screws/leverage points, but do you think the heat-gun approach would have helped when you opened your ECU?
Another idea that came to me would be to:
1) drill carefully through the ECU's plastic(nylon?) connector in two places (at front and back ends of connectors)
2) Turn ECU upside down and see if any oil comes out.
3) Flush with CRC QD.
4) Blow compressed air through one hole to clear anything out.
Does that sound insane or possibly that it might work, or am I just too shell-shocked after all that I've been through and things will be okay after installing isolator cables?
Thanks SunnyRayToronto. I had troubles finding an independent mechanic that was able to work on Mercedes.
- One over-filled the oil on my first engine and I abandoned him once that engine rattled to death with timing chain / guide / valve-piston contact issues.
- The mechanic that swapped the engine didn't bother to tell me that one of A/C pump bolts was missing when he replaced the first engine.
- Another that "specialized in Mercedes" didn't advise me that the solenoids hadn't been isolated with the fix cables,
- The fourth didn't torque down the new serpentine belt tensionner correctly and it dropped out one day and ripped open the air box in front of the belt.
So I went to MB stealership as a last hope due to rough idle, often almost stalling while decelerating at stop signs, and occassional warnings of "Check Battery/Alternator" while decelerating at stop signs.
I brought it into MB and they charged me $500 to tell me the car wasn't worth fixing. I then had to ask them what the appropriate idle RPM was? They said 800 and I said the tach showed 600. Then they offered to increase the RPM by 50 (the max permitted by their programming system).
I cleaned solenoid connectors and ECU connectors with CRC QD and it's running really well now except for occasional battery/alternator warning. I'm just a bit spooked which is why I want to check the ECU for oil. I suppose it wouldn't hurt to just fill the connector with CRC QD as you suggest. What do you think of the following approach for a Bosch ECU?
I realize that the c230 ECU doesn't have any screws/leverage points, but do you think the heat-gun approach would have helped when you opened your ECU?
Another idea that came to me would be to:
1) drill carefully through the ECU's plastic(nylon?) connector in two places (at front and back ends of connectors)
2) Turn ECU upside down and see if any oil comes out.
3) Flush with CRC QD.
4) Blow compressed air through one hole to clear anything out.
Does that sound insane or possibly that it might work, or am I just too shell-shocked after all that I've been through and things will be okay after installing isolator cables?
I think you're paranoid and overreacting,... which is exactly what the Mercedes STEALERship wants you to do,.... so they can make a crap load of money changing out your ECU.
Do NOT drill into the ECU,... you have absolutely no idea what's on the other side,.... MB came up with a number of circuit design for their ECU - even for same model year engine and type,... and if you drill in and hit something metal, metal bits will be flying all over the inside of the ECU.
Just spray the CRC QD Electronic Cleaner at the ECU plug,... from every angle, let it soak a bit and watch it dry,... if one part drys significantly faster than the rest, that part might be the one leaking oil into the ECU (rare),... if that happens then you just found a little hole to spray into your ECU!
I cleaned solenoid connectors and ECU connectors with CRC QD and it's running really well now except for occasional battery/alternator warning. I'm just a bit spooked which is why I want to check the ECU for oil. I suppose it wouldn't hurt to just fill the connector with CRC QD as you suggest. What do you think of the following approach for a Bosch ECU?
I realize that the c230 ECU doesn't have any screws/leverage points, but do you think the heat-gun approach would have helped when you opened your ECU?
Another idea that came to me would be to:
1) drill carefully through the ECU's plastic(nylon?) connector in two places (at front and back ends of connectors)
2) Turn ECU upside down and see if any oil comes out.
3) Flush with CRC QD.
4) Blow compressed air through one hole to clear anything out.
Does that sound insane or possibly that it might work, or am I just too shell-shocked after all that I've been through and things will be okay after installing isolator cables?
I agree with the advice to NOT drill into the ECU through the connectors or anywhere else.
Otherwise, if you saw oil on the ECU's connectors, then that is bad.
Yea, you "can" drive with just 3-lug nuts and not all 5 lug nuts on a wheel.
So, does that make someone smart for saving the weight and the time, or foolish?
Imho, it all depends on what you want to do with the car and how long you'll have it.
Any oil that got on the non conformal-coated PCB is bad news.
That PCB will use the CR*P lead-free CR*P solder CR*P CR*P CR*P that is now used because of RoHS.
Gotta say it again:
CR*P lead-free CR*P solder CR*P CR*P CR*P!!
Imho, one of the few pleasures/fun in life when I get to say that we sent a BGA out to be "de-balled". That's right, put the lead ***** on the BGA. We don't want no tin wiskers!
Back on topic...
Oil or water will corrode and degrade any solder joint it comes in contact with. And, oil won't evaporate away like water. So, it'll keep corroding and degrading any solder joint that it's in contact with.
Imho, that ECU is now in a similar position of a design that has input voltages passed the MAX or MIN input voltages of a chip.
Will it work, for how long? Imho, there are tons of horrible/poor/cr*p designs out there "that work" but don't meet spec.
The big question is always: How long will it work for?
Imho, the same could now be said for your ECU.
For me, I'm looking for my 2005 C230K to be in the same shape in 2035 as my ~30 year old Mustang is in now (very good).
Imho, a cheap heat gun (~$30) will get the cover off. Then, I'd use a non-linting shop towel (all done on an ESD mat), dab up any oil. Go outside, and blast CAN*S* of flux remover all over the board. Get it at Digikey, of course.
Also, get 1-2 cans spray conformal coating. Imho, that's better and easier to use than the brush on stuff. And conformal coat the board on both sides.
Let dry.
Use ??Gorilla Glue?? to glue the cover back on.
I'd also use clear 3M Lifetime silicon caulk around the edges. It's cheap, fast, easy, and provides extra protection.
As you may have guessed by my de-balling BGAs comments, I often do high-reliability designs.
In the end, it's your car, and your risk either way.
So, it's your choice.
One more time....
CR*P lead-free CR*P solder CR*P CR*P CR*P!
Well, I've been struggling with what to do with the car due to Mercedes telling me the ECU was full of oil. I had hoped to have the car for 20 years which is what I thought was possible with a Mercedes.
Anyway, tonight, I decided to take the risk. I pulled the ECU out of the car, grabbed my heat gun, put on an anti-static grounded bracelet, applied medium heat, to the edge of the lid and removed a bunch of black tarry rubber that seals the lid in a groove around the whole enclosure (messy scraping process -- please don't ask -- I cringed all the time). I vacuumed everything carefully without touching the PCB (cringe again). Then I carefully pried open the lid. There was not a drop of oil to be seen. Then I re-fitted the lid and temporarily secured the edges again using metal foil tape. Reinstalled the ECU in my car and took it for a drive. No issue.
See attached for the pics. Alas, there was no access to the other side of the PCB since the other half of the ECU enclosure is sandwiched between the connector and the PCB. But at least there's no sign of oil coming through the PCB through-holes or a couple other larger holes.
I plan to spray some flux remover on it and for good measure blast some CRC QD electronics cleaner through some of the larger PCB holes to the other side. At least I don't think that I have to worry about the ECU anymore. And regarding the Benz stealership telling me the ECU was full of oil, it appears that yes, they not only steal, but they lie.
Above: You can see the groove that goes around the whole PCB-ECU assembly. (After the photo, I cleaned out more of the black tarry stuff so that I can reseal the lid again.) This orientation is how it sits in the car.
Above: Here's the lid that sits in the groove around the PCB-ECU assembly. It was easiest to pry open at a corner and work slowly around.
Above: The chip in the top right is an AMD AM29F800BB-55SE which is 8 Mbit Flash boot memory. That would be the lowest point of the ECU when installed in the car so likely where oil would accumulate. So I guess if your car starts, this chip is working okay. http://www.alldatasheet.com/datashee...00BB-55SE.html
Last edited by stenodinson; 11-25-2016 at 02:14 AM.
Then I carefully pried open the lid. There was not a drop of oil to be seen. Then I re-fitted the lid and temporarily secured the edges again using metal foil tape. Reinstalled the ECU in my car and took it for a drive. No issue.
That's good news!!
Originally Posted by stenodinson
. And regarding the Benz stealership telling me the ECU was full of oil, it appears that yes, they not only steal, but they lie.
They may have said, and should have said:
Your ECU contains oil, or is full of oil.
From when I taught, I learned to qualifyeverything I say in situations like that.
Unless they called Miss Cloe at the Physic Hotline :-), then there's no way to say for sure about a bad or possible bad part. It's always their best guess.
Originally Posted by stenodinson
I had hoped to have the car for 20 years which is what I thought was possible with a Mercedes.
Uhm, yes and no.
Imho, MB is not, and never has been, near the reliability level of a Camry, Accord, or Ford Fusion.
Imho, if people want a good reliable car, buy one of those.
Onwards to the tech. :-)
You have a M271 engine just like mine.
As you've seen, there are a number of design issues because of cost and/or stupidity.
Imho..
1) The timing chain must be replaced within 60K miles.
2) The American version of the supercharged engine has too much boost for the POS built in "self draining catch can" to handle. Also, the supercharged engine should have a dual catch can setup.
Many OEM supercharged engines have the same issue.
A manufacture is not going to put in a catch can that the customer has to drain. So, the owners get many issues.
A) A big one right off is that the intercooler becomes a joke quickly since it gets coated with oil and then has very poor cooling ability.
B) On the M271, like some other engine, the intake valves get oil on the seats and that lead to poor sealing. IMHO, MB purposely screws the owners by being super sensitive to detecting misfires, and then they SCREW the owner by shutting off the injector for the misfiring cylinder - there by forcing the owner to get the engine fixed right away. Even if they owner doesn't live in an area that does emissions testing.
My ECU issue was the solder joint on one of the crystal oscillator (shiny metal thingy in your first image - centre of board, 1/3 up from bottom) feet that came loose from the circuit board (post# 30),... thus, if your ECU is still open, take a quick look to ensure no dry solder joint.
11-04-2012, 02:32 AM
That's right, put the lead ***** on the BGA. We don't want no tin wiskers! 
