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For reference the alternative to cloning the ECU is to go to MB, MB are not only proud of the ECU they force you to buy it as part of a service job. Online MB discount part dealers show the ECU for ~$1,400 (list is $2,200) but if you try to order they'll say they have to be shipped to an authorized agent and I'm doubtful an agent would work with anything but a part they sell at the full MB price. To add to that you'd need to get the vehicle towed to the dealer, they charge labor for installation and programming - so all in I recon you'll do well to get out for under $3k. The alternative, if your ECU can be read, is to buy a used ECU and get it cloned. You can get a used ECU for ~$350 and cloning is ~$200, guess which way I went!
After confirming the ECU was dead I opened it up, a failed capacitor had burned a hole in the circuit board, and it wasn't obvious to me that the data could be read for cloning. I spoke to a few people who did cloning and selected one who was most willing to discuss my situation and knowledgeable; they said while the ECU was shorted there was a good chance they could isolate the short and read the data files, there are up to four chips that need to be read. I would highly recommend the person I dealt with for cloning, PM me if you want his details, he was able to read all the data files and answered any questions I had.
I used www.car-parts.com and www.autopartsearch.com to find a used ECU, they have filters that try to give you compatible parts but generally I found them to be too restrictive. I was looking for a low mileage unit from a wrecked car, being wrecked implied the engine was running before its demise. The salvage yards sometimes know the mileage but nearly always know the VIN and there are online tools to give an approximate mileage. You'll pay about twice as much for a V8 ECU than a V6 and according to some online info a V6 should be clonable but that's something to try another day. When you rule out the people asking crazy amounts, and those that'll only take Zelle you don't end up with many options; I got a unit locally with ~100k miles. Generally speaking eBay was pricey and I had less confidence in the history of the unit.
There were various opinions about whether the ECU has to be opened to read and write the data, I was told it did and the process went smoothly. Having to open up the ECU would void any warranty so I didn't consider that a factor when buying. With the new ECU installed the car started normally, I'll run diagnostics to see if there's anything strange but assume all is good.
A question - does anyone understand all the info on the ECU label? Top row is the MB PN, bottom row left is BOSCH Motronic PN followed by date (YY-MM-DD), but what about 1375 1547 or A 003 446 70 40 or 37391547103303, or FD 09M02??? I'm hoping that one refers to the hardware which would help me dig into if a V6 ECU can work in a V8.
Thank you for sharing your experience with this great fix. It's a battle scar only comited owners have.
👏
I always like to see the reality of hardware electronic to look at the layout and what the components had to work through.
Here we see a nice 50Volts cap having a good life and we see a gaping hole charcoaled through by energy.
One would say the cap was aresting seriously bad vibes and overheated to an extreme short. see through computer ⚡
We got to hand it to Bosch for having so very few large capacitors... they downsized them into .1uF ceramics or filter the noise by other means. The injectors, solenoids, igniters are all the most difficult to interface with electronic in terms of noise and spike discharges.
The fact that runs nearly to perfection is a huge achievement.
I am sure all the forum regulars will be glad to help when needed. To be ECU safe, you may want to check the work of couple parts... :
ALTR,
GND STRAP,
BLT TENSIONR,
BAT,
.... .
We want to make sure we have a good stable voltage in a few places starting with the cluster display.
Spend some time to observe what kind of work the Alternator + GND Strap deliver to the car while driving (14.4v ...12.6v)
Last edited by CaliBenzDriver; 08-05-2023 at 12:19 AM.
Thank you for your replies. However I'm going to differ regarding a V6 ECU having a chance of working in a V8. On the 2010 to 2011 (and some 2012 models) the 350 and 550 engines the ECU is in the same location, same mounting and same physical connectors. Certainly, the firmware is different, I did some research on the wiring harnesses and there are differences, things like extra cylinder ignition and injector outputs are simply listed as unused pins on the V6 and there are one or two logic style connections that are different, I haven't gone through and checked all the pins but didn't see differences in the grounds. Furthermore, Bosch publishes a list of Motronic compatible PN that includes V6 and V8 numbers - see attached PDF. Against it being an option to use a V6 ECU are the cloning folk who say you must have an 8 cylinder ECU. This is why I was trying to understand the fields on the label, I'm hoping the A 003 446 77 40 shown on the below e350 ECU and the same on my ECU indicates the hardware in the box is the same. Beyond cost there are far more V6 ECU out there and with lower mileage.
Where did you get that chart? I want one... I figured it out for my car but it was partially taking a chance and see if it works. I bought a used ECU for an M157, I have an M278. Basically the same eng, just different displacement. The labels match up pretty good. The nice label is mine, the tossed around the yard and ran over a few times one is the junkyard. Actually the ECU was in great shape, but obviously the label wasn't so lucky. The color diff is sun light vs indoors.
As for all those other #'s, good luck! Reminds me of the rumor about the codes on canned food, where, as the rumor goes, the CIA tried to break the code and figure out what they meant, and failed. All I know is I failed trying on the ECU, but apparently just the big #'s on it matter. The actual part # for the car, if I look it up, has a couple more digits on the end of that main #, but I assume, maybe, they represent the tune loaded in it?
The junkyard one cost me $200 two years ago from an ebay junkyard. The link is dead but the seller was "benzeenautoparts" and they had various pix of the ECU and misc data, plus a fit list that included my car. I take the fitment list with a gain of salt, and an ebay list with a rock of salt, but these guys were correct. Plus it had the VIN so I pulled a report for it showing the totaled car, out of curiosity. Whole right side trashed but eng was no doubt fine. If anyone is in need, the price was excellent and sale, ship time etc was 5 stars.
See those four big black round things in a row the board pix? The V6 version of my eng has three and the ECU is shorter to match. I can only assume one set of those things per two cyls? No clue what they do but I'd imagine fuel and/or spark?
So, did the V6 version work on yours?
08-04-2023, 11:39 AM
