2015 with no fuel pressure problem

otep858 · Jan 24, 2020

I recently hit something in the road that ripped the wires off of the oil level sensor and i am trying to trace them back, however since that happened my fuel pump is not running, either by start button or by actuating the fuel pump within obd11. i can hear the relay click. but doesn't engage the pump either of them.. Does anyone know if the wires being disconnected from the oil level sensor will tell the ecm to not run the fuel pump? there is no other damage and the engine will crank just fine. not getting any more diesel at the filter. and yes there is plenty in the tank. also does anyone know the wire schematic for at the oil level sensor?

thundershorts · Jan 25, 2020

Why not repair the wiring for the oil level sensor and see if the lift pump operates? The in tank lift pump does not by itself generate any codes, only shows low rail pressure codes. It would be logical to cut fuel in event of low oil level, such as sudden loss as would happen if pan were damaged or car were in accident.

otep858 · Jan 25, 2020

I will fix that as soon as I can find a wire diagram for it. I just didn't know if anyone knew for sure or not if that would tell the pcm to cut fuel

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otep858 · Jan 27, 2020

Oil level sensor wires fixed. That wasn't what was causing the no signial to the fuel pump. Did find a bit of damage at the def tank and the wires that hook to the def pump. Have a new def pump coming. Hopefully that will be what is causing the problem

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740GLE · Jan 27, 2020

what the heck did you hit?

not sure if the lift tank wiring also follows the same routing of the DEF tank but with ODB11 or VCDS you should be able to verify the lift pump is working without def tank wiring or anything else.

Fixmy59bug · Jan 27, 2020

I could surmise how the faulty DEF wiring could prevent the engine from starting.

After all, if the ECU thinks the DEF tank is empty, the vehicle will not start.

So maybe that is what’s happening.

Good luck

otep858 · Jan 28, 2020

740GLE said:
what the heck did you hit?

not sure if the lift tank wiring also follows the same routing of the DEF tank but with ODB11 or VCDS you should be able to verify the lift pump is working without def tank wiring or anything else.

I was following a truck on icy roads, and a down rigging piece of metal came off the truck and I was unable to serve enough to miss it. It trashed both tires and rims on the passenger side. Only wire damage I can see were the oil level sensor and the def tank pump as you can see in the pic. And it's more from the plug into the pump itself. 4 wires connect and only 2 leads are still connected... I used obdelleven to activate the fuel pump and it says something about can't resolve some issue. Does have a fault code (P208A) that won't clear in the reductant tank.

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thundershorts · Jan 29, 2020

If the tank is anything like golf, there is the cover which looks like the scratched part that can be removed to expose the wiring. I had similar occurrence with my golf and ended up replacing tank with a used one from car-part.com for 100 bucks.

thundershorts · Jan 29, 2020

Good idea to replace the tank as in future you might get grief warranty wise as the damage is obvious. Its a item that junk yard doesn't consider a big seller so you ought to get one cheap, also not a hazmat item to ship.

740GLE · Jan 29, 2020

So the jolt of hitting that crap knocked damaged the connectors of the lift pump? That's just crazy bad luck.

IMO I'd be looking for just a new lift pump unless you see visual impact to the underside of the tank.

otep858 · Jan 30, 2020

740GLE said:
So the jolt of hitting that crap knocked damaged the connectors of the lift pump? That's just crazy bad luck.

IMO I'd be looking for just a new lift pump unless you see visual impact to the underside of the tank.

No it didnt damage the lift pump at all. it hit the def pump. which is getting replaced, (part should be here today). And im thinking that the damage to the def pump is telling the lift pump to cut fuel off.

oilhammer · Jan 30, 2020

I have seen cars that were in crashes have the fuel feed inside the tank on the lift pump break off.

740GLE · Jan 30, 2020

My apologies, i thought you posted a picture of the lift pump connections, but that's the DEF pump.

Either way, I feel you should be able to force the lift pump to move fuel and build pressure with zero DEF system installed if you have ODB11 or VCDS.

otep858 · Jan 30, 2020

740GLE said:
My apologies, i thought you posted a picture of the lift pump connections, but that's the DEF pump.

Either way, I feel you should be able to force the lift pump to move fuel and build pressure with zero DEF system installed if you have ODB11 or VCDS.

I wish I could remember the exact error obd11 gave me when trying to activate the lift pump. But it was something along the lines of unable to resolve some issue. Def pump will be here today so hopefully we will know soon if that has any effect on the lift pump.

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thundershorts · Jan 30, 2020

Does def pump run constantly or only during regen? A whole deft tank assembly used probably would cost a fraction of cost of just pump and would eliminate some guess work,besides the cosmetics. Dropping the def tank is pretty easy and quick and can be done on jack stands.

otep858 · Jan 30, 2020

thundershorts said:
Does def pump run constantly or only during regen? A whole deft tank assembly used probably would cost a fraction of cost of just pump and would eliminate some guess work,besides the cosmetics. Dropping the def tank is pretty easy and quick and can be done on jack stands.

Def tank problem is solved now. Just got the pump put on. Read the codes and no reductant tank codes now. However I still have no power going to the lift pump when I run the lift pump test in obd11. Same error code in the program that says "marginal conditions have not been met". And even tho my fuel tank is completely full the gauge reads empty. I thought for sure that since it all runs on a buss system that the transfer pump not engaging was directly related to the wires shorting on the def pump.. any help out there? I'm running out of reasons and leads to track down

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thundershorts · Jan 31, 2020

if your fuel gauge indicates empty, good chance the gauge sender/fuel pump assembly in the tank suffered damage from the impact. pop the rear seat up and check the intank unit for any wiring damage and/or pull unit out of tank. The unit costs about 300 list.

thundershorts · Jan 31, 2020

Def tank float level is likely damaged and that may or may not be easily replaceable.

otep858 · Jan 31, 2020

thundershorts said:
if your fuel gauge indicates empty, good chance the gauge sender/fuel pump assembly in the tank suffered damage from the impact. pop the rear seat up and check the intank unit for any wiring damage and/or pull unit out of tank. The unit costs about 300 list.

Is there a way to test the sending unit and fuel pump before just replacing it to make sure that is a problem? what is throwing me off here is that the car stayed running while i waited on a tow truck. and was shut off during transport. started the car up and backed it off the truck. the gauge went from almost full to having the e light on in a matter of 3 hours that i had waited for the tow truck. at the time i had just assumed that i had broke the return line. but i dont see any damage to the fuel lines anywhere. I suppose it could just be a coincidence that the fuel pump shot the **** at the same time that i had the accident.

tadawson · Jan 31, 2020

Bad pump won't cause the gauge to misread. I also suspect that something was damaged in that wiring, and it's possible that a damaged area in the harness became a failed area in the harness with all the manipulation, and/or possible exposure to the elements.

Myself, if I had the wiring diagrams, I'd test the harness from the pump/sender to where it terminates under the hood. I suspect that you will find something like a missing ground, which would (again, don't have the schematic, so might be another lead - if it were positive rail/control on ground) cause both the pump and the sender to lose a common lead.

thundershorts · Feb 1, 2020

Pump and fuel sender are one unit, so if either sender or pump aren't working, problem is in unit. Pull it out and test.

thundershorts · Feb 1, 2020

As i remember from replacing mine, sender is a tube with the float inside, rather than a float arm, but ;ll look at the one pulled out today.

otep858 · Feb 1, 2020

thundershorts said:
As i remember from replacing mine, sender is a tube with the float inside, rather than a float arm, but ;ll look at the one pulled out today.

Do you just ohm the outside leads to the pump. One for power and the other for ground. Do you know what the ohm should be between? And why would that also throw the gauge off by that much?

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thundershorts · Feb 1, 2020

Different leads for float ,low fuel light, and fuel pump. easy to see wiring with pump/float out. If the impact was great enough to dislodge float in fuel tank, its most likely the def level float was damaged as well.

otep858 · Feb 5, 2020

thundershorts said:
Different leads for float ,low fuel light, and fuel pump. easy to see wiring with pump/float out. If the impact was great enough to dislodge float in fuel tank, its most likely the def level float was damaged as well.

Any idea what the different leads should ohm out at? ill include a pic of the plug. the 2 outside (1 and 5) are for the lift pump motor but not sure what ohm they should be at im getting .7 ohm across them now. also i discovered that the floor pan is somewhat damaged by the fuel tank not sure if the fuel tank got shoved upward or what. ill include the pics of that. i tried putting 12 volts to the positive side of the pump and hooking the ground. and the pump doesnt turn then either. altho it does spark when the leads are touched.. what would be a good way to read the leads on the 3 middle small wires for the sending unit?
Also im getting no codes or problems def related now that damage was fixed with replacing that def pump.

thundershorts · Feb 5, 2020

Might as well pull the pump out since you said the tank was hit hard enough to affect floor. Connections will be obvious with it out. A few minutes removes the pump with the seat out.

otep858 · Feb 6, 2020

thundershorts said:
Might as well pull the pump out since you said the tank was hit hard enough to affect floor. Connections will be obvious with it out. A few minutes removes the pump with the seat out.

What still bothers me is that when using a test probe i still get np power back at the plug when its not hooked to the pump. fuse and relay are good

thundershorts · Feb 6, 2020

The tank being plastic, probably deflected, dented upward, damaging the float, pump assy which reaches to the very bottom of the tank. Its not a big deal to pull the assembly out and rule out that it was toasted by the impact. You can see at the bottom of the tank a low round area which if it shows any sign of impact/gouges that should be your clue

otep858 · Feb 6, 2020

thundershorts said:
The tank being plastic, probably deflected, dented upward, damaging the float, pump assy which reaches to the very bottom of the tank. Its not a big deal to pull the assembly out and rule out that it was toasted by the impact. You can see at the bottom of the tank a low round area which if it shows any sign of impact/gouges that should be your clue

I pulled the fuel pump assembly out today, and its toast. broke in several places, new one on the way. ill keep you updated if i make it back on the road

thundershorts · Feb 7, 2020

Gee, thats a real surprise. Hopefully new assy will still fit in tank. Next concern will be if the def float and other stuff in that tank are toasted as well.

2015 with no fuel pressure problem

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