Pressure in the fuel low pressure circuit, is too high.
Out Of Control!!
Joined: Apr 2019
Posts: 11,922
Likes: 6,775
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
TWO THUMBS UP
@CaliBenzDriver You Are The Man!!!!
Problem fixed!!
I received the FSCU module yesterday and proceed to install it, but first using this Launch Creader Elite 2.0 MB scanner, I back up coding from old FSCU then disconnect battery, replace FSCU, reconnect battery, restore coding, clear all codes with scanner, run scanner again and no more codes.
I drove the car for a few miles this morning, when I got home connect scanner again and no codes.
Checking live data, fuel rail pressure now shows 57 psi.
Problem fixed!!
I received the FSCU module yesterday and proceed to install it, but first using this Launch Creader Elite 2.0 MB scanner, I back up coding from old FSCU then disconnect battery, replace FSCU, reconnect battery, restore coding, clear all codes with scanner, run scanner again and no more codes.
I drove the car for a few miles this morning, when I got home connect scanner again and no codes.
Checking live data, fuel rail pressure now shows 57 psi.
I just help you with hints and steps.
Remember that you need to locate the source of water to disable repeat game installments.
It's always about ROOT CAUSE!
Thread Starter
Junior Member
Joined: Jan 2017
Posts: 20
Likes: 5
From: Ventura County, California.
2010 E350
Main Fuel pump which is under rear seat passenger side, is now quieter, I think the bad FSCU was causing the noise in fuel pump.
In my research about fuel filter discover that the fuel filter is also a secondary fuel pump, which is located under rear seat driver side, I haven't replace that, do you thing it will be a good idea to replace it?
Super Member
Joined: Mar 2024
Posts: 618
Likes: 241
From: Chicago
19 GLA45, 86 560SL, former: 14 E550 4Matic, 09 E350 4Matic, 83 240D manual, 78 450SLC, 81 500SLC
If you replace the module under the right rear seat, also replace the one under the left rear seat. You'll probably be going back in there again soon if you don't. It's 3x more work to replace 2 of those modules separately, and only 1.5x more work to replace them both at the same time compared to one. At least the way I did mine. This is because they connect to each other in the tank and you need to pull them both at least partially to do either one.
Out Of Control!!
Joined: Apr 2019
Posts: 11,922
Likes: 6,775
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Yes the water source has been fixed, I purchase this FSCU used from Ebay, same part number, same everything on the module label but was removed from 2011 E550, mine is 2010 E350, the back up and restore of coding went really smooth, I like this scanner!
Main Fuel pump which is under rear seat passenger side, is now quieter, I think the bad FSCU was causing the noise in fuel pump.
In my research about fuel filter discover that the fuel filter is also a secondary fuel pump, which is located under rear seat driver side, I haven't replace that, do you thing it will be a good idea to replace it?
Main Fuel pump which is under rear seat passenger side, is now quieter, I think the bad FSCU was causing the noise in fuel pump.
In my research about fuel filter discover that the fuel filter is also a secondary fuel pump, which is located under rear seat driver side, I haven't replace that, do you thing it will be a good idea to replace it?
You can leave the standard tank troubles alone for now.
Or
you can spend ressources on tank items that are not due for service. I would not.
Last edited by CaliBenzDriver; Jul 25, 2025 at 12:31 AM.
MBWorld Fanatic!
Joined: May 2018
Posts: 6,600
Likes: 6,547
From: Jakarta-Indonesia
2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
Yes the water source has been fixed, I purchase this FSCU used from Ebay, same part number, same everything on the module label but was removed from 2011 E550, mine is 2010 E350, the back up and restore of coding went really smooth, I like this scanner!
Main Fuel pump which is under rear seat passenger side, is now quieter, I think the bad FSCU was causing the noise in fuel pump.
In my research about fuel filter discover that the fuel filter is also a secondary fuel pump, which is located under rear seat driver side, I haven't replace that, do you thing it will be a good idea to replace it?
Main Fuel pump which is under rear seat passenger side, is now quieter, I think the bad FSCU was causing the noise in fuel pump.
In my research about fuel filter discover that the fuel filter is also a secondary fuel pump, which is located under rear seat driver side, I haven't replace that, do you thing it will be a good idea to replace it?
Yes, you MUST replace the fuel filter on the LEFT side of the tank, now ur car is 14ish years old.
You cut it open and you will be surprised how dirty it can be.........
Stay safe when doing fuel tank yah.....
Thread Starter
Junior Member
Joined: Jan 2017
Posts: 20
Likes: 5
From: Ventura County, California.
2010 E350
How many miles did you say were on the car?
If you replace the module under the right rear seat, also replace the one under the left rear seat. You'll probably be going back in there again soon if you don't. It's 3x more work to replace 2 of those modules separately, and only 1.5x more work to replace them both at the same time compared to one. At least the way I did mine. This is because they connect to each other in the tank and you need to pull them both at least partially to do either one.
If you replace the module under the right rear seat, also replace the one under the left rear seat. You'll probably be going back in there again soon if you don't. It's 3x more work to replace 2 of those modules separately, and only 1.5x more work to replace them both at the same time compared to one. At least the way I did mine. This is because they connect to each other in the tank and you need to pull them both at least partially to do either one.
Thread Starter
Junior Member
Joined: Jan 2017
Posts: 20
Likes: 5
From: Ventura County, California.
2010 E350
Its not actually a secondary pump, it is a venturi effect "pump" ( no motor, just a venturi ) to make sure RIGHT side tank where the fuel pump is, is aways full of fuel....so that pump does not get fuel starve.
Yes, you MUST replace the fuel filter on the LEFT side of the tank, now ur car is 14ish years old.
You cut it open and you will be surprised how dirty it can be.........
Stay safe when doing fuel tank yah.....
Yes, you MUST replace the fuel filter on the LEFT side of the tank, now ur car is 14ish years old.
You cut it open and you will be surprised how dirty it can be.........
Stay safe when doing fuel tank yah.....
Thread Starter
Junior Member
Joined: Jan 2017
Posts: 20
Likes: 5
From: Ventura County, California.
2010 E350
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