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P254000 - low pressure fuel circuit pressure sensor signal implausible

41K views 9 replies 6 participants last post by  Carrrsten  
#1 · (Edited)
Just completed a major service - resealed leaking front chain case covers, replaced leaking water pump, replaced spark plugs, and replaced dying battery with a Duracell AGM battery on my 2013 E350 4matic Wagon with 157K miles. Did all this work myself with the help of Mercedes-Benz WIS and YouTube videos. BTW, the WIS is wrong on the last step for removing the intake plenum. I'll post on that in a separate thread.

The car had several DTC codes (but no check-engine light) that I thought were caused by a weak battery. Now all codes but one are gone. The check-engine light is still off. The one stubborn code that remains is P254000 and it shows as current and stored. I have the Mercedes Star Diagnostic System (SDS) with Mercedes Xentry software. The Xentry diagnostic log is attached below. It shows the fault code and the freeze frame data from the "N118 Control Unit 'Fuel Pump' (FSCU07)". The "stored" codes for the Motor Electronics (ME) control unit were triggered when I forgot to reconnect a couple of electrical connectors at the back of the intake plenum when finishing the above work. Once I plugged in the connectors, the fault codes turned from "current" to "stored." SDS refuses to delete these fault codes even though they are "stored" and not "current." Perhaps this is so because of the "current" fuel pump control unit code.

I have searched the internet for the fuel pump fault code P254000 and Mercedes w212 E350 but found little to no useful info. Can anyone decipher the Xentry log and help me troubleshoot the problem?

Any subscribers to Star TekInfo here? Could you please search P254000 and w212 on Star TekInfo and let me know if you find anything?
 

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#2 · (Edited)
Came across the following Technical Service Bulletin at benzworld - https://www.benzworld.org/attachments/li47-20-p-061013_ver_1-pdf.2525810/. Found it via a google search. Full text search at benzworld for the keyword P254000 returns only my current post. The TSB refers to figures/pictures that are not included in the linked document. Found the attached pictures on another site.

This document is not related to w212. Is the content still relevant? At this point, I only have the P254000 code from the FSCU (Fuel System Control Unit). However, couple of years ago, the FSCU showed stored codes P254000 and P008700, two of the three codes mentioned in the above Technical Service Bulletin. My car doesn't show any symptoms listed in the TSB - no check engine light and no engine jolting/shaking. So I'm wondering if these codes can become a problem when I least expect it.
 

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#8 · (Edited)
Hello everybody, I have a 2016 Face-lift Eclass w212 RWD sedan with 3.5L 6 cylinder engine showing the code P254000 as current and stored, I've already scanned the whole system with no other codes at all , and the vehicle drives smooth with no problems at all, Considering that I have 0 experience in any auto related repairs or diagnostic knowledge; and knowing that my Auto mechanic recommended me to just ignore it, Is there anything I can do to get rid of this code ? If anyone else got any solution please post Thank you in advance for any help
 
#10 ·
The fuel pump ECU hints at the fuel pressure is to low. Of course you checked if you can hear the fuel pump when activating EZS. For 2 or 3 seconds you hear the fuel pump buzz. If so you need to check the pressure on the engine, there is a measuring point on the rail. If you don't have the special tools, I would start looking for possible leaks. If all is well you probably have a bad fuel pump. The fuel tank has two so you have to figure out a way to determine which one is bad