Mercedes-Benz Forum banner

Engine Control Unit

6K views 6 replies 4 participants last post by  Patman1 
#1 ·
I have a 2005 C280 which has been down / off road for two months now because of a faulty engine control module/unit. Local price for the unit is prohibitive. Part number A 272 153 45 79. Any suggestions?
 
#2 ·
First I would suggest posting in the correct forum. You need to post in the W203 forum. Second, go to car-part.com and search for a used one on there. Do your research though and make sure it is plug and play; in other words, make sure it will NOT require any programming to make sure it will work. If this is the case, you may need to consult a local Benz mechanic that has the ability to program them, and ask if they would be willing to install the used module for you. In fact, our local Benz dealer was willing to install some used modules on my fathers s430 due to the insane cost of the new ones, so if you ask around, you are bound to find someone to do it.
 
#3 ·
This is indeed the wrong forum for your car. However, swapping ECMs from one ME-SFI Mercedes to another is a little more involved than plug and play. In fact, not even a new unit would be plug and play. They will all require coding to your vehicle. It is possible to swap ECMs from a donor car, but you better find someone who knows their way around a circuit board and a soldering iron. There is an EEPROM chip on your ECM that contains vehicle information that needs to be desoldered and transplanted to the donor ECM. Needless to say, many things can go wrong with this.
 
#5 ·
MB-W202 yes, but not in your case. Your C280 uses HFM-SFI that does NOT have the ECM coded to the car, so if you ever needed to swap, it would just be plug and play. In my case, my 1996 C220 also has HFM-SFI, but coded to the car. There is no EEPROM on HFM-SFI though, vehicle data is stored on the main chip.
 
#7 ·
Ahh yes, my original issue was that the secondady air injection pump would turn on for a few seconds at idle, when the engine was already warm. I considered swapping my ECM out with a used one I got from eBay, but that's when I started learning about DAS and all that. Turns out, I'd have to first unlock the used ECM I got before I can code it, and given the cost involved to fix something on what is otherwise a perfectly operational ECM, I decided to put that on hold. Luckily, my car is becoming popular at my local dealership, and I am regular customer there, so maybe I'll be able to have the ECM coded for free at some point.

I also befriended an electrical engineer who also happens to be a petrolhead. I might borrow his oscilloscope and jam its prongs into my CAN bus and see if the signal is healthy. Wonky CAN bus signals can cause weird behaviour. I believe the signal to activate the secondary air injection comes through there, since it's not on the pinout for any of the other wires coming out of the ECM.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top