W212 3.5CGI HIGH PRESSURE FUEL PUMP
12-09-2018, 01:02 PM
#1
Junior Member
Thread Starter
W212 3.5CGI HIGH PRESSURE FUEL PUMP
HI Everyone just a quick question I’m hoping someone can answer I’ve had what I thought were battery issues on my 2012 m276 3.5cgi. I’ve had symptoms of slow cranking only by a few seconds extra but it’s something I’ve definitely noticed lately. I have had both battery’s tested by Mercedes last week and they have reported them to be absolutely fine.
Today I’ve done a diagnostic test using my icarsoft MBII unit and no fault codes were found. I then started delving further into the 46 different sections on the machine and under engine I have 2 codes stored. These codes are not coming up on the normal diagnostic check and I have no EML light so it’s very strange. The codes are relating to the HIGH PRESSURE FUEL PUMP and they state I have a leak. These codes can’t be deleted either and I’ve not noticed any symptoms other than this slow crank which would probably now explain that reason.
Ive found the part I need at around £250 a lot less than I was expecting, but has anyone else had these issues on this engine ? It’s a 2012 M276.952 3.5 CGI PETROL.
I belive the part is located at the back of the engine has anyone replaced one themselves? Is there a how to guide anywhere or is this a garage only job ?
Thanks inadvance
Today I’ve done a diagnostic test using my icarsoft MBII unit and no fault codes were found. I then started delving further into the 46 different sections on the machine and under engine I have 2 codes stored. These codes are not coming up on the normal diagnostic check and I have no EML light so it’s very strange. The codes are relating to the HIGH PRESSURE FUEL PUMP and they state I have a leak. These codes can’t be deleted either and I’ve not noticed any symptoms other than this slow crank which would probably now explain that reason.
Ive found the part I need at around £250 a lot less than I was expecting, but has anyone else had these issues on this engine ? It’s a 2012 M276.952 3.5 CGI PETROL.
I belive the part is located at the back of the engine has anyone replaced one themselves? Is there a how to guide anywhere or is this a garage only job ?
Thanks inadvance
12-09-2018, 02:59 PM
#2
MBWorld Fanatic!
Some thoughts:
Are you able to verify that the fuel pressure regulator is ok? I would check that first before the fuel pump as a failing regulator is a common cause of extended cranking time.
By slow cranking I assume that you are not looking at the starter itself? Did the shop check amperage draw when cranking?
Oops I see CGI, my comments may be off base but I left them in case they may relate to something.
Are you able to verify that the fuel pressure regulator is ok? I would check that first before the fuel pump as a failing regulator is a common cause of extended cranking time.
By slow cranking I assume that you are not looking at the starter itself? Did the shop check amperage draw when cranking?
Oops I see CGI, my comments may be off base but I left them in case they may relate to something.
12-09-2018, 06:02 PM
#3
Junior Member
Thread Starter
Thanks for the reply MUD i appreciate it I’ve checked the codes again this evening and listed them below with the listed description which would definitely lead me to the high pressure fuel pump and not a regulator ? With regards to the battery check by Mercedes I’m not sure what was actually checked other than they were both marked green to say they passed inspection
P1D2909 ( AN INTERNAL LEAK WAS DETECTED IN THE HIGH PRESSURE FUEL PUMP. THERE IS A COMPONENT FAULT
P008796 ( THE FUEL PRESSURE IN THE SYSTEM IS TOO LOW. THERE IS AN INTERNAL COMPONENT FAULT
P1D2909 ( AN INTERNAL LEAK WAS DETECTED IN THE HIGH PRESSURE FUEL PUMP. THERE IS A COMPONENT FAULT
P008796 ( THE FUEL PRESSURE IN THE SYSTEM IS TOO LOW. THERE IS AN INTERNAL COMPONENT FAULT
12-10-2018, 06:43 AM
#4
Junior Member
Thread Starter
How or where can I obtain the documentation that Mercedes use on how to proceed with the replacement
like how to kind of thing ? I’ve contacted MERCEDES this morning and the part is correct £275 with discount so I just need to find out how to replace it
like how to kind of thing ? I’ve contacted MERCEDES this morning and the part is correct £275 with discount so I just need to find out how to replace it
12-10-2018, 09:35 AM
#5
Out Of Control!!
Join Date: Jul 2003
Location: North Scottsdale, AZ
Posts: 15,903
Received 4,417 Likes
on
3,146 Posts
'71 Pinto
Check your PM.
The following users liked this post:
Wenglish1984 (12-10-2018)
12-07-2019, 10:13 PM
#7
Mine was M276.957 engine, 3.5L NA. High pressure pump sits behind the bank1 crankshaft end and I found there is very confined space to access for tools. My problem now is I have high rail pressure during idle which is actually the same as when cruise (2000PSI), leading to a high negative fuel trim long and short. I'm thinking that the pressure solenoid may go out or PCM gives wrong command signal (i once shorted the alternator positive with chasis ground when replacing alternator where I'm concerning I fried the PCM).
