Sarthur2013

I have a 2017 C43 AMG Coupe, and I sent my ECU out to get tuned, and I just got it back and tried reinstalling it and I get an error saying inoperative, see owner's manual. The engine doesn't try to start or do anything. I called the shop that tuned it and they told me to disconnect the battery for twenty minutes, then reinstall the ECU and reconnect the battery. I tried this and it didn't change anything. The shop is closed now and I'm trying to get it fixed tonight. Does anybody have any ideas how to fix it without erasing the ECU and wiping the tune they just installed?

Thanks for any help!

PaulE550

Did you try unplugging the ECU, checking to make sure none of the pins in the connectors are bent or damaged and then plugging the ECU back in making sure both connectors are fully seated? If the ECU isn't fully plugged in, you will get what you are describing.

Sarthur2013

I tried the whole sequence of disconnecting the battery, then the ECU, and reinstalled it again, making sure none of the pins were bent and that the connection was solid, but I still get the following error:

PaulE550

Well then it sounds like your ECU may have been bricked. Your car is not recognizing the ECU. Nothing happens when you try to start the car at all correct? No clicking from the starter? No engine cranking noise? Just sits there completely quiet right?
Strongly recommend you contact whoever tuned your ECU first thing in the morning. Likely you will have to send it back to them and if you're very lucky, they will be able to flash it back to stock and it will work. They may have simply over-written the portion of the
ECU code that mates the ECU to your vehicle. Shouldn't have to touch any of that code for a tune, but who knows at this point. If they can't re-flash it back to stock, then you're likely looking at having to buy a new ECU from MB. Obviously the replacement ECU is
not going to be covered by MB warranty. You will also have to give your existing ECU back to MB when the new one comes in. Likely MB will have to order the new one from Germany, that is preprogrammed for your particular VIN so it will recognize your car. Let is know how it goes.

Narry

HI
check the pins on the connector needed use a light to see or the pins inside ecu is damage
because these new car ecu have to be bench flashed best of luck
narry
ps sometimes checksum doest match also since I have all device ktag cmd magic motor sports

getmercd

I am guessing you didn't unplug the battery when you removed the ECU and shipped it lol I have heard of this tons of times because people don't follow the instructions. Not a huge deal, though. If the ECU reset didn't work then you probably have to send it back for the tuner to reboot it. I would also recommend checking the pins and connectors. Good luck!

Sarthur2013

Yep, you’re 100% right. I spoke to the tuners today and that was the issue. I didn’t have the right tool to disconnect the Mercedes battery when I sent it in, so I thought it would be no big deal. Totally my fault, so I’m shipping it back to the tuner and they’ll reset it for me. Hopefully second time is the charm!

Dogtag114

deleted