Bad ECU?
Thread Starter
Newbie
Joined: Aug 2024
Posts: 3
Likes: 0
W211 E63
Bad ECU?
Not quite sure where to start. here is the full story. I have had this car for about a year now with no problems until recently. parked the car in the garage, came out next morning to go to work and got a no crank no start. I found out the starter relay was stuck open. got a new relay from the dealership and car worked fine for about 24hr. Got home from work and parked the car in the garage, came out the next morning and got a no crank no start. thought it was the starter considering it's the original starter from factory. got a new starter and replaced it and got a new relay and replaced it. no crank no start still. had the car towed to a garage who was able to read the modules in the car and said they had about 5 sheets of codes and didn't know where to start. they cleared the codes with Star and the car started again. long story short they couldn't get to the car for a while, so I had to go to a new garage. this garage said no codes came up other than my alternator was failing. I replaced the alternator and the battery because I thought that could be causing problems. they cleared the alternator code and car started again. parked the car in garage and wouldn't you know it, no crank no start again. When trying to start the car I now hear the starter relay click over and the fuel pump prime but still won't crank.
here are all the new parts I have thrown at it.
At this point I am starting to wonder if the ECU needs to be reprogrammed?
Any help would be welcomed as I am starting to go crazy with this car.
https://drive.google.com/file/d/1cBL...usp=drive_link
here are all the new parts I have thrown at it.
- alternator
- battery
- starter
- starter relay
- new key batteries
At this point I am starting to wonder if the ECU needs to be reprogrammed?
Any help would be welcomed as I am starting to go crazy with this car.
https://drive.google.com/file/d/1cBL...usp=drive_link
Member
Joined: Jan 2016
Posts: 80
Likes: 6
W211 E63
Do you have a 63 or 55? My 2007 63 needed a wiring harness and ECU back in like 2019, so it possible they go bad on these cars. Not saying that is the case just saying it does happen. It was a nightmare experience with the car being in multiple shops (one of which was an excellent indy MB mechanic) for almost a year before going to the dealer for another month or two.
My car died while at a stop light then wouldn't start so a little different scenario
Nobody ever figured out what exactly caused it but the dealers' best guess was it had something to do with a missing/unattached ground strap
My car died while at a stop light then wouldn't start so a little different scenario
Nobody ever figured out what exactly caused it but the dealers' best guess was it had something to do with a missing/unattached ground strap
Thread Starter
Newbie
Joined: Aug 2024
Posts: 3
Likes: 0
W211 E63
Do you have a 63 or 55? My 2007 63 needed a wiring harness and ECU back in like 2019, so it possible they go bad on these cars. Not saying that is the case just saying it does happen. It was a nightmare experience with the car being in multiple shops (one of which was an excellent indy MB mechanic) for almost a year before going to the dealer for another month or two.
My car died while at a stop light then wouldn't start so a little different scenario
Nobody ever figured out what exactly caused it but the dealers' best guess was it had something to do with a missing/unattached ground strap
My car died while at a stop light then wouldn't start so a little different scenario
Nobody ever figured out what exactly caused it but the dealers' best guess was it had something to do with a missing/unattached ground strap
I am really hoping it’s the ECU because I really don’t want to have to rewire this car. Also it’s a 63
MBWorld Fanatic!
Joined: Jan 2014
Posts: 3,975
Likes: 1,321
From: Republic of Texas
'99 and '05 E55 AMG
Safely raise the car. Jumper the starter solenoid, see if the engine cranks and starts with key in run position
More tips here:
https://mbworld.org/forums/w211-amg/...-no-crank.html
Also, consider a bad module is stopping the CANBUS. X30/5 CAN-C connector under door sill driver's side ties multiple critical modules to the ECU. Connect a cheap CANBUS monitor to that connector. If no data on the bus, pull each connector one at a time until data appears. The last connector pulled leads to the bad module. I posted a link to a Reddit video of a W211 with no crank no start issue. In that video, disconnecting the TCU eliminated the issue. Of course the TCU had to be replaced.
https://mbworld.org/forums/w211-amg/...-no-start.html
EDIT: WIS information here. Zipped file will be larger than 1.2GB so you may need an aftermarket file downloader (Win11 chokes at 1GB). Full schematics and WIS in this file.
https://charm.li/Mercedes%20Benz/2007/
More tips here:
https://mbworld.org/forums/w211-amg/...-no-crank.html
Also, consider a bad module is stopping the CANBUS. X30/5 CAN-C connector under door sill driver's side ties multiple critical modules to the ECU. Connect a cheap CANBUS monitor to that connector. If no data on the bus, pull each connector one at a time until data appears. The last connector pulled leads to the bad module. I posted a link to a Reddit video of a W211 with no crank no start issue. In that video, disconnecting the TCU eliminated the issue. Of course the TCU had to be replaced.
https://mbworld.org/forums/w211-amg/...-no-start.html
EDIT: WIS information here. Zipped file will be larger than 1.2GB so you may need an aftermarket file downloader (Win11 chokes at 1GB). Full schematics and WIS in this file.
https://charm.li/Mercedes%20Benz/2007/
Last edited by bbirdwell; Apr 29, 2025 at 09:43 PM.
