This is my second W212, I had a E350 that developed the crack in the left side low pressure fuel pump cover. After paying the indie too much money, it was fixed by replacing the unit. I have since sold that and bought a '15 E400, (which I love BTW, what a great car!) The fuel smell developed recently so I popped the covers off under the rear seat and behold, the low pressure pump on the left had cracks in the plastic houseing and a puddle of fuel. Being very mechanically inclinded, I watched the YouTube videos, read the forums and ordered the part. (The part came from AutohausAZZ and was OEM MB) Prior to the repair, no running issues or codes. I had recently ran through the codes with my iCar so know it was clear. Installing the unit was pretty straight forward, completed in about an hour and a half. Started the car and no leaks! WooHoo! after about 2 - 3 minutes of running, it stalled. Now it starts and shuts off. Connected the iCar, codes are as follows:
P253900 Th pressure sensor of the low pressure fuel pump has a malfunction
U010987 Communication with control module "Fuel pump" has a malfunction, the message is missing
P206812 The right fuel level sensor has a short circuit to positive. There is a short cirucit to positive
U145700 The Signal 'Fuel level' frpm the rear signal acquisition and actuation module was not received by the instrument cluster.
P053F94 The fuel pressure during a cold start is unreasonable. There is an unexpected instruction
P062800 The output for the fuel pump has a short circuit to ground
P062700 The output for the fuel pump has an electrical fault or open circuit
P1CCF00 High pressure could not be built up during engine start
So how is that for a plethora of codes?
I pulled the right side pump and double checked the internal connections, all fine.
Rechecked the connections on the left side, all good.
I am suspecting the sensor on the new unit is defective...

Any clues, idea, input or offers to buy me a drink? I will attack it again tomorrow but any input or help would be greatly appreciated!!

Michael A

Dumb question at 3 AM. Don't you have to code in the new pump? You disconnected the battery before you switched the units ? Ok, back to sleep.

Actually, no I didn't. I removed the fuel pump fuse and let the car run until the pressure droped and stalled. I will give it a try.
Thanks!

Did you perform a code clear after running the pump, with the fuse pulled? Certainly, that would cause a code or two..

Smiles, You are my hero. Disconnected the battery, let it sit about 30 minutes (chores on Saturday), started it up, after about 3 seconds of trying to figure out what happened, it smoothed out and runs like a top. Cleared the "historic" codes and retest, clean and green, off to put some miles on her.

THANKS AGAIN!!

So we know things just cant be that easy!

The car starts and runs great, no fuel smell, running perfect on 125 mile trip today. BUT When I set out driving, I get a message the auto dimming headlight system is disabled, and the lane warning system is disabled... How to I re-enable these two systems?

could be windshield is dirty in front of top cameras.

A co-worker had this same issue in his W212. All it required in his case was resetting the errors using my Launch code reader. That’s where I’d start.

I did just that, went in with my iCar and cleared all the codes from the previous failures. Working like a champ now!!

Thanks to all for the input and help!

Glad you are all good! I think i deserve a like for the assist. Helps bolster my fragile ego