Fuel Gauge help

[will.bates94]

Had my fuel pump replaced at a local shop and got it back with the fuel light flashing in the display. The gauge was also reading incorrectly, and when filled up it only reads around half. I read the code via vagcom and here are the results...

1 Fault Found:
00771 - Fuel Level Sensor (G)
30-00 - Open or Short to Plus


I pulled the rear seat and removed the cover. It looked like everything was hooked up fine....

Do I need to recali the fuel level sender?

[Luis_Heineken]

send the car back to the shop, so they can fix it

[jayiszraw]

send the car back to the shop, so they can fix it

X2 especially if it was working before you brought it to the shop.

[diagnosticator]

Try disconnecting the battery to reboot the cluster, first.

[will.bates94]

Try disconnecting the battery to reboot the cluster, first.

This was already cycled since I had my ECU replaced recently by an actual audi dealer.

[old guy]

Sure sounds like a bad connection as a result of replacing the fuel pump. It's a pretty simple arrangement. Unplug the connector with the black and green wire visible in this pic:



Unplug the connector and check for continuity as shown in this pic. No need to remove the level sensor. Just unplug it and use your multimeter to test the continuity. The reading should be between 50 Ω → 300 Ω depending upon a full or empty tank.



I suspect the problem is either the harness didn't get plugged back in or it has a poor connection.

[will.bates94]

Not getting continuity or resistance readings. Also its not possible because I dont have an aftermarket fuel pump like you have pictures and theres a one way harness for the two wires. Not possible to connect wrong. Is there something under that cover that was disconnected wrong or left unhooked? Ill be seeing the guy tomorrow also about it.

[old guy]

Then how about this pic? I just grabbed the first one I could find that showed the fuel level sensor connection:



If you are not getting any continuity checking at the harness plug there is something wrong with the level sensor or the wire to the sensor is broken. A third possibility is that the sensor arm was damaged and the sensor sliding arm contacts are no longer making contact to the potentiometer windings.

[will.bates94]

Then how about this pic? I just grabbed the first one I could find that showed the fuel level sensor connection:



If you are not getting any continuity checking at the harness plug there is something wrong with the level sensor or the wire to the sensor is broken. A third possibility is that the sensor arm was damaged and the sensor sliding arm contacts are no longer making contact to the potentiometer windings.

So here's the story so far.

It is registering when I pump fuel. The needle will rise to just above half and go down accurately. Its like the needle is off by a half tank or so. Does it just need to relearn its position? Did the shop accidentally turn the car on while the sensor was disconnected?

[old guy]

Two possibilities come to mind. first is installation error: Clicky click. Another possibility is that the shop damaged the fuel level sensor during the pump installation. You can test that by checking the resistance as shown in post #6. The reading should be between 50 Ω → 300 Ω depending upon a full or empty tank.

[will.bates94]

Two possibilities come to mind. first is installation error: Clicky click. Another possibility is that the shop damaged the fuel level sensor during the pump installation. You can test that by checking the resistance as shown in post #6. The reading should be between 50 Ω → 300 Ω depending upon a full or empty tank.

Thanks for the reply man.

I tried to check the resistance and couldn't get anything to show up. Ill check out that link.

[will.bates94]

Very interesting, but I don't have a return line on my a4..... Ill even send pictures. On my external cap, the nipple is capped off, no hose.

when i get time ill pull the seat and take pics of what I mean....

[will.bates94]

Two possibilities come to mind. first is installation error: Clicky click. Another possibility is that the shop damaged the fuel level sensor during the pump installation. You can test that by checking the resistance as shown in post #6. The reading should be between 50 Ω → 300 Ω depending upon a full or empty tank.

Well I dug the A4 back out after putting my MK7 Gti away until the roads clear up here. I fixed a hose that looked to possibly be in the way but am still getting the same code. I just filled it up in hopes to just adjust the needle to where I want it to be but first i checked the measuring blocks for the resistance it was reading. Below is a screenshot. Does this help with knowing what could be wrong or if the fuel sender is broken? If its broken, do you have a part number for the level sender and not just the whole basket?

2015-12-30 14_27_39-VCDS Release 15.7.3_ 17-Instruments, Measuring Blocks _ Basic Settings.jpg

[old guy]

The range should be 50 Ω → 300 Ω depending upon a full or empty tank so it sounds like you have a problem with either the potentiometer or the wiring. It's damn expensive. Clicky click® Maybe you can find one at a scrap yard. Part # 8E0-919-673-AG.

Good luck!

[will.bates94]

The range should be 50 Ω → 300 Ω depending upon a full or empty tank so it sounds like you have a problem with either the potentiometer or the wiring. It's damn expensive. Clicky click® Maybe you can find one at a scrap yard. Part # 8E0-919-673-AG.

Good luck!

Why am I seeing two different leveling sensors for our cars on ecs tuning's website? Do we just have on level or two? Also thank you for the quick reply. Is that the latest revision part number? I also have a 3.0 V6 and am not seeing this part.

[old guy]

If you have a Quattro the fuel tank is shaped like an upside-down "U". Consequently there are two level sensors. One for each side. The one I linked is on the riders side along with the fuel pump.

[will.bates94]

If you have a Quattro the fuel tank is shaped like an upside-down "U". Consequently there are two level sensors. One for each side. The one I linked is on the riders side along with the fuel pump.

I see. Here is the part number for the passenger side one I had found, sorry I don't know how to hyperlink 8E0919673AT

Any idea as to why they use different sensors?

[old guy]

One sensor is incorporated into the suction jet transfer pump (drivers side). This device is used to keep buth legs of the "U" filled equally once you go below ~ ½ tank of fuel. The other one is installed separately on the rider's side along with the fuel pump. There is no reason to suspect the sender unit on the drivers side since it wasn't touched during the fuel pump replacement. I'm pretty sure your issue is with the one on the rider's side.

[old guy]

Oops! I just looked up the part number that you referenced. I just assumed it was for the drivers side sender. It isn't.

The difference in the two senders depends upon the model year of your B6. The one I linked if for up to Vin number 8E-5-065001 The split is in the 2005 model year. The one you referenced is for an '05 or later.

[will.bates94]

Oops! I just looked up the part number that you referenced. I just assumed it was for the drivers side sender. It isn't.

The difference in the two senders depends upon the model year of your B6. The one I linked if for up to Vin number 8E-5-065001 The split is in the 2005 model year. The one you referenced is for an '05 or later.

I see, so I need a pre 05 sender since mine is a 2003, which by the looks of it will use the same one you sent me. Also, do you know of a good method of getting the fuel out of the tank? I have yet to find one...

[old guy]

The easiest way by far is to just run it down to around½ tank and you can reach in and remove the sender unit without removing the pump. Here's a link to removing the unit. Be sure to read the complete thread on how to check out you current sender unit to see if it is working properly. Clicky click®

[will.bates94]

The easiest way by far is to just run it down to around½ tank and you can reach in and remove the sender unit without removing the pump. Here's a link to removing the unit. Be sure to read the complete thread on how to check out you current sender unit to see if it is working properly. Clicky click®

So upon removing the fuel sending unit, i found out it wasnt even connected. But now I cannot find the leads that plug into the sender. What part of the tank should I look in? I felt around and couldnt find them. Any tips?

[diagnosticator]

If for some reason you don't want to burn the fuel to lower the tank level by driving around, the only other way to get the fuel out of the tank is by using a 12 volt fuel pump that has either a hose connection for both the inlet and outlet ports on the pump, or a pump that is submerged in the fuel with only a discharge port hose connection. The pump suction hose or the submersible pump is passed through the tank access hole with the cover removed, and the sender unit loose in the tank top. The pump power wires need to be connected to a 12 volt battery or a 12 volt power supply remotely placed away from the pump and fuel tank. You will need a couple of 5 gallon gasoline jugs to receive and store the fuel removed from the tank.

Siphoning the fuel out of the tank does not work because the fuel level in the tank is to close to the ground, and there is not enough vertical distance to cause the fuel to flow with a siphon.

[will.bates94]

If for some reason you don't want to burn the fuel to lower the tank level by driving around, the only other way to get the fuel out of the tank is by using a 12 volt fuel pump that has a hose connection for both the inlet and outlet ports on the pump. The pump suction hose is passed through the tank access hole with the cover removed, and the sender unit loose in the tank top. The pump power wires need to be connected to a 12 volt battery or a 12 volt power supply remotely placed away from the pump and fuel tank. You will need a couple of 5 gallon gasoline jugs to receive and store the fuel removed from the tank.

Siphoning the fuel out of the tank does not work because the fuel level in the tank is to close to the ground, and there is not enough vertical distance to cause the fuel to flow with a siphon.

I let it run down to less than an 1/8th of a tank. Got the sensor hooked back up and everything is working perfect now!

[diagnosticator]

I let it run down to less than an 1/8th of a tank. Got the sensor hooked back up and everything is working perfect now!

Good job! Thanks for the update!

[will.bates94]

Good job! Thanks for the update!

Thank you guys so much for the help! Much appreciated.

Sent from my Nexus 6P using Tapatalk

[old guy]

Thank you guys so much for the help! Much appreciated.

Sent from my Nexus 6P using Tapatalk

LOL!! Thanks for the update! I was just getting ready to go out in the cold dark to pull the rear seat and take a picture for you. Now i can drink another glass of wine instead!

[will.bates94]

LOL!! Thanks for the update! I was just getting ready to go out in the cold dark to pull the rear seat and take a picture for you. Now i can drink another glass of wine instead!

I appreciate the effort you have put in for me man... Thanks again! Couldn't of figured it out without you. Almost bought a new fuel sender last summer because of this shit lmao

Sent from my Nexus 6P using Tapatalk