help on fuel level gauge (electrical problems)

[victimdumper]

since ive had the car ive had a fuel problem. My gauge wont go past 3/8th of the tank no matter how full the tank is and i constantly have the orange low fuel light on 24/7.
(though anything below 3/8th of a tank reads perfect and miles till empty is perfect)
ive searched and found that this is usually a problem with the sending unit, and i pull the code:

00438 - Fuel Supply Sensor 2 (G169)
30-00 - Open or Short to Plus

the same one everyone who has a fuel gauge problem seems to have. now the difference is that ive followed this:
http://www.audizine.com/forum/showth...l-sending-unit

and used this to see if there was a problem with it in the first place:
http://www.audiworld.com/tech/eng104.shtml

both of the units come up as working properly on the DMM and for some reason the code keeps coming back, ive opened them up and tried to clean them
but every time i clear the code the son of a bitch comes right back within a few moments.
seeing as it wouldnt make sense to replace a unit that appears to be working...
im going to have to assume that the problem lies with the wires that run from the tank to the dash possible?

has anyone had a similar problem or have any idea of where i should trouble shoot this?
its driving me crazy hearing that beep when i turn the car on and that symbol always there

[A4 Moda]

Gotta check your wiring that connects to the tank.

chances are pin is bent or is seriously dirty.

Use a flashlight and check the pins on the tank itself as well as the female pins on the connector.

The other possibility - (though it wouldn't throw a fault to power code ) - is that the actual arm isn't moving correctly. It's not freely floating inside the tank, so you're not seeing anything above 3/8.

Anyway - if both of these fail to provide you with a solution - it might be time to replace that sensor. It's been sitting in fuel since 2002.

GL

[victimdumper]

i checked the pins in-tank and everything checks out, ill try to check all of the other connections i can, i just dont know where they are other than the ones at the tank.
i don't think its the arm not moving correctly because when the sensor is out everything swings fine, also i agree that it wouldn't send a code.

thanks for the info though, ill keep searching next chance i get.
ehhh and the old sensor "seems" fine so im being stubborn on replacing it just yet haha

also if its another pin somewhere and not the sensors fault, then ill be buying a new sensor for nothing

[old guy]

I replaced my fuel pump ~ 3 weeks ago and about a week later my fuel gauge began acting up. It would drop from ½ tank to below ¼ tank and the next day go back up to ½ tank. I pulled the right side float sensor and cleaned the contacts but it continued to fluctuate. I finally narrowed it down to the where the right side float sensor plugs into the connection underneath the fuel pump cover. Although the plug felt tight it wasn’t making good contact with the two connector blades. I cleaned and tightened the connector and (knock on wood) so far it has worked properly.

Edit: I should add that I used some 400 grit sandpaper on the connector blades to make sure I had a clean contact surface.

Edit: Another update. The connector didn't cure it. This did: Clicky click

[victimdumper]

hmmm, I will double check the connectors, i did look briefly at them but like you said they appeared to be making a connection,
but maybe that's why when i clear the codes they take a minute of driving before coming back.

[diagnosticator]

Either pull the instrument cluster fuses or disconnect the battery for a few min. This will force the IC to reboot on power supply restore when the fuses or battery are reconnected. This procedure usually corrects the fuel gage error for awhile at least.

[victimdumper]

that's actually the very first thing i tried, hoping that it would fix it before i went through this other stuff but alas it did not
but i will try it again now that I've reached into the fuel tank a few times and messed with the connectors, maybe ill get lucky

[Dotpage]

Any news? I have exactly the same issue...

[old guy]

Try this: Clicky click

[victimdumper]

Try this: Clicky click

thanks old guy, i Actualy did find that thread of yours when i was troubleshooting and it didnt fix it =/

Any news? I have exactly the same issue...

and no good news eh, when I first made this thread I spent like 3 straight days trying to figure this out and still haven't found the cause of the problem.
even though everything seemed to check out electrically.
I kinda gave up for the time being, seeing as my gauge is still accurate from 3/8th of a tank down to 0 haha.

The only thing I have yet to do it replace the sending units...
but I didn't want to, because oddly enough both units checked out to read full and empty correctly when I ran a multimeter over them in the tank, so I didnt want to replace a good sending unit.

I plan on giving it another go now that the weather is warmer again and getting to the bottom of it (I hope)
maybe testing for continuity in the physical wire that connect the sending units to the dash

[Dotpage]

Cool. My car is in the shop now, I'll update with results. Already replaced sender and problem persists...

[victimdumper]

Cool. My car is in the shop now, I'll update with results. Already replaced sender and problem persists...

please do! especially if they can find the problem, I would love to fix this and have some damn closure on it haha

[Dotpage]

Problem solved. The APR dealer loaded a Quattro version... So the computer was expecting data from a sensor that does not exist... All this time and money for a dealer mistake...

[victimdumper]

Problem solved. The APR dealer loaded a Quattro version... So the computer was expecting data from a sensor that does not exist... All this time and money for a dealer mistake...

hmmmm probably not my problem since i am quattro, but glad you solved yours
I could always check to see if my car is looking for FWD units

[tim04USPa4]

hmmmm probably not my problem since i am quattro, but glad you solved yours
I could always check to see if my car is looking for FWD units

Having just swapped from FWD to quattro, if that number is off in the gauge cluseter (VAGcom setting) that will screw things up pretty badly, but it should still read. My tank read around 1/4-1/3 high on the FWD settings with a quattro tank, but it still read all across the gauge (from when I filled up, still worked until I corrected the value to read for two sending units).

Did you follow the wire from the two sending units and make sure the purple wire(s) from the sending units to the cluster dont have a short or are stripped somewhere? To the best of my knowledge they read off resistance for the reading from the tank, ergo if something is goofing up it could possibly be giving a false reading. Only two wires deal with the gauge, purple for the gauge value, then black for a ground.

Just throwing some ideas out there. Good luck.

Edit: Just read the rest of the responses and you mentioned physically checking the wires. Shouldve read first

[Dotpage]

Good luck with yours. I guess checking on the VagCom for missed configurations was my contribution

[victimdumper]

Good luck with yours. I guess checking on the VagCom for missed configurations was my contribution

Thanks, its appreciated! any idea where the configurations for the fuel sending unit are in VagCom? I'll Prob go out in look for it in a few minutes anyways

[robivin]

I had same problem
00438 - Fuel Supply Sensor 2 (G169)
30-00 - Open or Short to B+

On quattro version you have 2 fuel level sensors on each side of car.
On driver side is sensor 2. I disconnect jack and connect it back and problem solved :)
Images are here: https://drive.google.com/folderview?...jA&usp=sharing