2012 ML350 Bluetec Fuel pump/controller help
Thread Starter
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Joined: Mar 2013
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R320
2012 ML350 Bluetec Fuel pump/controller help
Hey Guys,
my ML350 Bluetech has 105K miles on it and has been running like a top. Last week I parked it and when I went to start it, the next morning, it cranked with no start. pulled codes and got a P0087 LOW FUEL PRESSURE code. Changed fuel filter but not getting fuel to the filter, and I can't hear the fuel pump running. Checked fuses. All are fine.
Figured I'd trouble shoot from easiest to most difficult but can't find the following information.
What I'm wondering is:
1. I can't find anything that Identifies whether any of the relays under the center seat are responsible for the fuel pump. Anyone know if they are? If so, which one?
2. Where is the Fuel pump control Unit Located. Is there any way to test without just replacing?
Thanks. I appreciate the help
Jason
my ML350 Bluetech has 105K miles on it and has been running like a top. Last week I parked it and when I went to start it, the next morning, it cranked with no start. pulled codes and got a P0087 LOW FUEL PRESSURE code. Changed fuel filter but not getting fuel to the filter, and I can't hear the fuel pump running. Checked fuses. All are fine.
Figured I'd trouble shoot from easiest to most difficult but can't find the following information.
What I'm wondering is:
1. I can't find anything that Identifies whether any of the relays under the center seat are responsible for the fuel pump. Anyone know if they are? If so, which one?
2. Where is the Fuel pump control Unit Located. Is there any way to test without just replacing?
Thanks. I appreciate the help
Jason
Out Of Control!!
Joined: Sep 2018
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From: unbegrenzt
2017 GLE350 4MATIC
Have you downloaded EPC/WIS? Around $6 on ebay. Diagrams and module locations are contained therein.
Have you found the paper (hardcopy) fuse diagram in your vehicle? Mercedes typically stores them inside one of the fuse boxes.
Have you found the paper (hardcopy) fuse diagram in your vehicle? Mercedes typically stores them inside one of the fuse boxes.
Thread Starter
Newbie
Joined: Mar 2013
Posts: 5
Likes: 5
R320
Problem solved
Just wanted to circle back around and close the thread on my particular problem, just in case anyone else has a similar problem. on my 2012 ML350 BT, I had the issue where it would intermittantly crank with no start. Code was P0087. Low fuel pressure. First attempt at repair was to change the fuel filter. After replacement, the car started and ran great for two weeks, then the same problem. In my research, I found it could be either the fuel pump control module or the pump. The fuel pump control module is located under the carpet behind the passenger side rear seat. It requires removal of the rear seat to access it. I changed it out first, but still the low fuel pressure, crank and no start persisted. I had hoped it was the module, as the fuel pump change is much more labor intensive.
I can confirm that the W166 DOES NOT have the removable cover in the footwell of the passenger compartment, so it necessitated dropping the fuel tank. I removed the exhaust and driveline, but you may be able to get enough room simply by dropping the tank down to the driveline and tipping it. A couple observations:
1. The fuel filler neck has a flap internal to the tank. You can remove it from the tank with minimal fuel leaking out. In my case, I stuck a screwdriver in and drained the remaining fuel from the tank to make things easier.
2. Removal of the fuel pump was pretty straightforward but would have been much easier If I had the special tool. This would also make reinstalling easier. It was difficult to get the lid tight enough after reinstalling to prevent leaks.
3. Was a pretty involved process. Took about 6 hours start to finish.
Hope this helps others.
Jason
I can confirm that the W166 DOES NOT have the removable cover in the footwell of the passenger compartment, so it necessitated dropping the fuel tank. I removed the exhaust and driveline, but you may be able to get enough room simply by dropping the tank down to the driveline and tipping it. A couple observations:
1. The fuel filler neck has a flap internal to the tank. You can remove it from the tank with minimal fuel leaking out. In my case, I stuck a screwdriver in and drained the remaining fuel from the tank to make things easier.
2. Removal of the fuel pump was pretty straightforward but would have been much easier If I had the special tool. This would also make reinstalling easier. It was difficult to get the lid tight enough after reinstalling to prevent leaks.
3. Was a pretty involved process. Took about 6 hours start to finish.
Hope this helps others.
Jason
