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Cannot establish communication with Fuel pump control module
2012 S550 is in the crank no start condition. I thought it was because the fuel pump was bad. I took the fuel pump out and it indeed appears to be bad. When I apply 12V to black and red line, it came up for a second and then the wires get too hot. I replaced it with a new aftermarker pump. However, the car still cranks but doesn't start. The fuses F118/128 and the fuel pump relays tested fine. I can feel the relay click. However, I still get no voltage on the new fuel pump.
Sentry reports in the picture. Cannot communicate with N118. I looked everywhere for it and cannot find where the blasted box is. I would be ever so grateful if someone would point out the way to diagnose myself into starting this car.
Based on the videos I saw it can be.
1. Behind the air bag cover on the rear passenger side.
2. Behind the airbag cover on the driver side e.g. where the fuel filter and sending units are
3. In the trunk behind the passenger seat wall.
At the front of the driver side rear seat. You have to pull the carpets and the airbag cover aside. It is held by two clips on the top and by the screw from the front.
No, I think the fuel pump module is bad. By the looks of it. I see some evidence of oxidation on the contacts. I think sometimes in the past, the rear window was left open and rain got into it. Water would go down the seat cushion and then towards the front where this module seats. I ordered a new one and should know for sure once it arrives.
Ok, the fuel pump controller was replaced. The fuel pump came online and the car started right up
Can you tell me where you bought the controller? I'm having the same issue but mine started after replacing the fuel pump and filter with new units direct from Mercedes. All fuses and relay tests ok but car will not fire up. I wanted to buy a new unit from Mercedes but it says the part is discontinued and no longer for sale. I'm trying to avoid putting a used unit in because I don't want it to fail for some odd reason. Any help is appreciated.
Can you tell me where you bought the controller? I'm having the same issue but mine started after replacing the fuel pump and filter with new units direct from Mercedes. All fuses and relay tests ok but car will not fire up. I wanted to buy a new unit from Mercedes but it says the part is discontinued and no longer for sale. I'm trying to avoid putting a used unit in because I don't want it to fail for some odd reason. Any help is appreciated.
I just got a used one from ebay. What your symptoms? Do you get the same code? Do you hear fuel pump turn on when you try to start the car?
All I hear is the fuel pump relay engage. No pump engaging. I've checked fuses 30, 118 and 128. All are good as well as the fuel pump relay. The code in getting is a short in the fuel pressure sensor which has already been replaced. And still nothing. So I'm thinking the controller may be shot. It came up with a low pressure code and I replaced the pump assembly and filter assembly with new parts from Mercedes. Drove the car the next day locally to the bank and came back outside and she wouldn't start.
All I hear is the fuel pump relay engage. No pump engaging. I've checked fuses 30, 118 and 128. All are good as well as the fuel pump relay. The code in getting is a short in the fuel pressure sensor which has already been replaced. And still nothing. So I'm thinking the controller may be shot. It came up with a low pressure code and I replaced the pump assembly and filter assembly with new parts from Mercedes. Drove the car the next day locally to the bank and came back outside and she wouldn't start.
If the relay engages but the pump does not run should it be a problem with the pump or connection in the wire harness to it?
All I hear is the fuel pump relay engage. No pump engaging. I've checked fuses 30, 118 and 128. All are good as well as the fuel pump relay. The code in getting is a short in the fuel pressure sensor which has already been replaced. And still nothing. So I'm thinking the controller may be shot. It came up with a low pressure code and I replaced the pump assembly and filter assembly with new parts from Mercedes. Drove the car the next day locally to the bank and came back outside and she wouldn't start.
I've heard the same click and no pump engagement until I replaced the fuel controller. However, I had a code stating no communication with the fuel controller
The weird part is that this started after the pump was replaced and the new pump ran originally. I drove the car a couple of times before it suddenly stopped when I parked the car. I don't have xentry so I'm not as informed as I should be. But I've checked everything else electrically. Currently waiting on a used controller to be delivered. This is on a 2008 S65 with 51k miles.
Just an update, installed new pump controller and she fired up right away. I'm not sure what caused it to fail, there was no corrosion on the old one and no fuses were blown.
I had something similar and it turned out to be a ground issue near the rear of the car—cleaning and tightening the ground connections fixed the communication error for me.
I ran into something similar on a C-Class and found a damaged wire under the rear seat that was causing the module to lose communication. I had replaced some connectors before using aftermarket Caterpillar parts just because they were durable and easy to get, and they worked fine for that setup. Worth checking the wiring harness closely; corrosion or even pinched wires can throw things off without blowing a fuse.
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