2012 Mercedes-Benz S550 (m278) Misfires Left Bank (cyl 5, 6, 7, 8)
Senior Member
Joined: May 2019
Posts: 305
Likes: 114
2007 S550
Update: It is the infamous “motor oil in engine wiring harness” that plagues m278 engines. It has leaked enough to reach the oxygen sensors on the left bank, hence the misfire codes.
They have also stated that it has reached the ECU a little bit. They will be attempting a cleaning of all affected areas and see if that fixes it. I have a feeling neither they nor I want to replace the whole harness.
I don’t understand how an engine can be designed like this.
They have also stated that it has reached the ECU a little bit. They will be attempting a cleaning of all affected areas and see if that fixes it. I have a feeling neither they nor I want to replace the whole harness.
I don’t understand how an engine can be designed like this.
Thread Starter
Member
Joined: Feb 2019
Posts: 150
Likes: 109
2012 Mercedes-Benz S550
Senior Member
Joined: May 2019
Posts: 305
Likes: 114
2007 S550
Anywhere that sells the adjuster magnets will have them.
https://www.fcpeuro.com/products/mer...des-2711500156
https://www.fcpeuro.com/products/mer...des-2711500156
Out Of Control!!
Joined: Sep 2018
Posts: 14,671
Likes: 4,574
From: unbegrenzt
2017 GLE350 4MATIC
Update: It is the infamous “motor oil in engine wiring harness” that plagues m278 engines. It has leaked enough to reach the oxygen sensors on the left bank, hence the misfire codes.
They have also stated that it has reached the ECU a little bit. They will be attempting a cleaning of all affected areas and see if that fixes it. I have a feeling neither they nor I want to replace the whole harness.
I don’t understand how an engine can be designed like this.
They have also stated that it has reached the ECU a little bit. They will be attempting a cleaning of all affected areas and see if that fixes it. I have a feeling neither they nor I want to replace the whole harness.
I don’t understand how an engine can be designed like this.
MB is no different than Kia or Dodge in this regard.
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04 E55 AMG (totaled), 07 S550 4Matic, 14 E63S
Anecdotally I read a lot of issues on cars that have done a lot of sitting, or maybe short trips (basically lower than average mileage for the age). For example, my 2014 E63S with 99k had only a little oil on the cam position sensor plugs and none at the computer. Twice the mileage of yours.
Junior Member
Joined: Nov 2022
Posts: 24
Likes: 2
From: Toronto
2012 E550
Update: It is the infamous “motor oil in engine wiring harness” that plagues m278 engines. It has leaked enough to reach the oxygen sensors on the left bank, hence the misfire codes.
They have also stated that it has reached the ECU a little bit. They will be attempting a cleaning of all affected areas and see if that fixes it. I have a feeling neither they nor I want to replace the whole harness.
I don’t understand how an engine can be designed like this.
They have also stated that it has reached the ECU a little bit. They will be attempting a cleaning of all affected areas and see if that fixes it. I have a feeling neither they nor I want to replace the whole harness.
I don’t understand how an engine can be designed like this.
I was driving home from work yesterday when I had the engine light flash, then go solid after sometime...I limped back home but haven't driven since.
My odb 2 scanner says cylinders 5,6,7 misfiring. Guess it could be the same. Was wondering if I should take it to Robinsons in toronto or to the dealership!!?
How much did it cost you?
Last edited by VarunBajaj; May 30, 2024 at 11:22 PM.
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Joined: Aug 2014
Posts: 5,319
Likes: 1,675
S500
thats three posts going round now on funny idle and strange misfires on the V8s - this link to the same engine in another part of this forum shows an owner going through major huddles trying to resolve
https://mbworld.org/forums/cl55-amg-...8-low-rpm.html
as it was some special dealer tool magic that resolved - makes me wonder with the point here about not using it much !
about 4 years back on later cars it turned out some extra software in the engine ECU needed to be removed... if the car sat greater than 3 week of no use, a mistake in the engine management software incorrectly interpreted data from the ambient temperature sensor and threw a fake EML (why does it even look at it - other than it was how the dieselgate emission scandal on the merc tractors functioned !!! ) these cars get fixed by flashing an update at the engine ECU....
and why am I mentioning it - my car just before the fuel consumption fell off a cliff, dropping 30% at low speed for the last 18 months threw an ambient temp fault just before that happened - it was counting down as as I drove - did it twice, then the outside temp readings have worked correctly ever since - but fuel use is horrific - I can't find a cause or any faults (FYI mates CL did EXACTLY the same thing about the same time !!!)
.
https://mbworld.org/forums/cl55-amg-...8-low-rpm.html
as it was some special dealer tool magic that resolved - makes me wonder with the point here about not using it much !
about 4 years back on later cars it turned out some extra software in the engine ECU needed to be removed... if the car sat greater than 3 week of no use, a mistake in the engine management software incorrectly interpreted data from the ambient temperature sensor and threw a fake EML (why does it even look at it - other than it was how the dieselgate emission scandal on the merc tractors functioned !!! ) these cars get fixed by flashing an update at the engine ECU....
and why am I mentioning it - my car just before the fuel consumption fell off a cliff, dropping 30% at low speed for the last 18 months threw an ambient temp fault just before that happened - it was counting down as as I drove - did it twice, then the outside temp readings have worked correctly ever since - but fuel use is horrific - I can't find a cause or any faults (FYI mates CL did EXACTLY the same thing about the same time !!!)
.
Last edited by BOTUS; May 31, 2024 at 04:00 AM.
Thread Starter
Member
Joined: Feb 2019
Posts: 150
Likes: 109
2012 Mercedes-Benz S550
so all that work done previously was for nothing? It was the O2 sensors!? Is the car working fine right now?
I was driving home from work yesterday when I had the engine light flash, then go solid after sometime...I limped back home but haven't driven since.
My odb 2 scanner says cylinders 5,6,7 misfiring. Guess it could be the same. Was wondering if I should take it to Robinsons in toronto or to the dealership!!?
How much did it cost you?
I was driving home from work yesterday when I had the engine light flash, then go solid after sometime...I limped back home but haven't driven since.
My odb 2 scanner says cylinders 5,6,7 misfiring. Guess it could be the same. Was wondering if I should take it to Robinsons in toronto or to the dealership!!?
How much did it cost you?
The issue is that the oil in the harness can ruin all sorts of things, in my case it was the O2 sensors. Cost was about $1500, new sensors, harness cleaning. I would NOT take it to the dealership, they are the ones that swore up and down that it is the coils and plugs. You need a mercedes only performance shop, preferably one that has knowledge in M278 engines. Most shops would say you need a new harness to the tune of $10,000+. The owner of my shop is super knowledgeable and has engineered a way to clean them instead of replacing.
Also look into the purchasing the pigtails that connect to the camshaft sensors, I have linked them in previous posts.
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Joined: Sep 2020
Posts: 53
Likes: 10
I have a 2012 W221 as well. My car has been jerking a lot lately when I tried to throttle faster. Today, it jerked a whole bunch and then flashed the check engine light. I turned the car off and started it about 5 minutes later and the light was gone. It seemed fine until about couple minutes into driving, did the same where I throttle harder and light came back. I checked the code and it seems to be:
P030185 - Combustion misfiring of cylinder 1 has been detected. There is a signal above the permissible limit value.
Р030085 - Combustion misfiring has been detected. There is a signal above the permissible limit value
P06AF00 - The torque control system has triggered torque limitation or shutoff of the combustion engine
Before I go replacing parts, would this be a similar issue to what you experienced? Could there possibly be oil in the harness / cam shaft sensor? Would you be able to guide me on where this harness is so that I can inspect it? Any videos on it? Any help will greatly be appreciated!
P030185 - Combustion misfiring of cylinder 1 has been detected. There is a signal above the permissible limit value.
Р030085 - Combustion misfiring has been detected. There is a signal above the permissible limit value
P06AF00 - The torque control system has triggered torque limitation or shutoff of the combustion engine
Before I go replacing parts, would this be a similar issue to what you experienced? Could there possibly be oil in the harness / cam shaft sensor? Would you be able to guide me on where this harness is so that I can inspect it? Any videos on it? Any help will greatly be appreciated!
Thread Starter
Member
Joined: Feb 2019
Posts: 150
Likes: 109
2012 Mercedes-Benz S550
I have a 2012 W221 as well. My car has been jerking a lot lately when I tried to throttle faster. Today, it jerked a whole bunch and then flashed the check engine light. I turned the car off and started it about 5 minutes later and the light was gone. It seemed fine until about couple minutes into driving, did the same where I throttle harder and light came back. I checked the code and it seems to be:
P030185 - Combustion misfiring of cylinder 1 has been detected. There is a signal above the permissible limit value.
Р030085 - Combustion misfiring has been detected. There is a signal above the permissible limit value
P06AF00 - The torque control system has triggered torque limitation or shutoff of the combustion engine
Before I go replacing parts, would this be a similar issue to what you experienced? Could there possibly be oil in the harness / cam shaft sensor? Would you be able to guide me on where this harness is so that I can inspect it? Any videos on it? Any help will greatly be appreciated!
P030185 - Combustion misfiring of cylinder 1 has been detected. There is a signal above the permissible limit value.
Р030085 - Combustion misfiring has been detected. There is a signal above the permissible limit value
P06AF00 - The torque control system has triggered torque limitation or shutoff of the combustion engine
Before I go replacing parts, would this be a similar issue to what you experienced? Could there possibly be oil in the harness / cam shaft sensor? Would you be able to guide me on where this harness is so that I can inspect it? Any videos on it? Any help will greatly be appreciated!
Junior Member
Joined: Feb 2008
Posts: 47
Likes: 6
2001 ML320, 1998 E430
I just wanted to add my experience with my 2012 CLS550. Misfiring after warming up, Bank 2, mainly cylinder #5, but also 6, 7 and 8. Computer keeps going in and out of closed loop, runs smooth in open loop, switches to close the loop, starts, misfiring, kicks out of close loop back in the open move and run smoother again. Over and over. Bank 2 lean codes as well. The problem with her being the O2 sensors, replaced all 4 of them, problem solved!
