Allroad 2.5tdi Low Fuel Level Sensor (G210)

[bagpipingandy]

Hi all, just spent the last 6 hours after towing the car home trying to solve whats up with it, can any one help & shed some light:

Its my 2000 Allroad AKE:
since December I have run out of diesel twice, low fuel warning on the dash had come on around 35miles left and it was dead at 20 miles left both times, I just though its a bit unussual but my own fault for going so low on fuel, so since then i have been weary monitoring the fuel guage vrs mileage left and carried a spare can in the boot, anyway
so today driving home, car full to the roof with stuff, I noted I need to get diesel approx 50 miles left, no fuel light on, nearly at the garage and the glow plug light starts to flash, strange I though, may be the brake light switch and head to the garage car running ok, stop to fill it up, and then the car would not start sitting at the pump, turns over but not starting, tried a few things, but thought it need the codes read, so get towed home, get VCDS on it and the only code I get:

01441 - Low Fuel Level Sensor (G210)
27-00 - Implausible Signal

aftersome reading up I get an ohmeter on the the g210 level sender and I get 450ohms dead on, this is good, so mess about with a few things learning how it all works. Pump in the tank runs fine on cranking, realised the pump doesn't push to the fuel filter. Codes cleared nothing comes back and so last resort crack open a few fuel lines to injectors, a lot of cranking :( until diesel starts coming out and eventually it fires, great, but why wouldn't it start at the garage?, the car was only off for 2-3mins max when filling up.

My questions: Can this G210 sensor actually stop the car from starting??

after it started at home I removed the plug to the G210 sensor & I get the flashing glow plug, i stopped the car, trying to simulate my earlier scenario but it starts again ok with an open circuit on G210???:confused: can an implausable signal on this level sensor actually stop the car firing??

any ideas as I am sure i didn't run out of diesel, but am keen to find a resolution to what i think may have been the issues before and it may be a recurring problem?

can I change just this sensor if need be?

any ideas, experiences and solutions greatly welcomed

Andy

[Crasher]

When faced with that fault code, without GFF to guide you through, all you can do is replace the fuel pump unit 4B0 906 087 BC and see what happens. This is available after market if you can find someone who sells Meat & Doria or Hoffa.

[bagpipingandy]

Thanks for the reply crasher, some more Q's

If the baffle housing runs out of diesel will it give the fault "implausable signal"? or would it give a low level error?
i'm trying to figure out if the g210 sensor is faulty or if the baffle housing has actually run out of diesel,

Also Can the g210 sensor prevent the car starting?

Any info welcomed

Andy

Ps what is GFF to guide through.:Blush2:

[kite]

GFF=guided fault finding

Sent from my GT-I9100 using Tapatalk

[Crasher]

yes, sorry, Guided Fault Finding. VAG took away all of the fault code info on the AKE engine and made it all GFF applicable so I use VAS PC to work with problems like this.

[Kyojitsu]

The answer I believe is yes as it happened to my Allroad after one of the fuel level sensors was incorrectly fitted by my indie mechanic. There are 3 sensors in all on the Allroad as it has a 'saddlebag' tank - so you'll need to check them all.

I was driving home over Christmas on motorway at night with what I thought was a quarter tank - glow plug comes on, no low fuel warning, car limps to a stop and will not start at all. Starter motor turns but no firing (no fuel). Recovered on truck.

Turns out the new sensor had been put in 180deg the wrong way round. This I assume sent an incorrect signal and fuel gauge gave faulty reading but ECU could not resolve the lack of fuel being drawn through the fuel pump (I assume) and shuts everything down. Slightly different to your story as you hadn't run out of fuel but the sensor implied that you had - again couldn't be resolved by ECU so perhaps it's to save potential damage.

Anyway - sensor was correctly fitted and car fired up no problem (with some fuel added!).

[bagpipingandy]

can the intank pump assembly be removed without the special tool to undo the bayonet style fitment?

I might have a look in there to make sure it is clean and all hoses are intact, check all level sensors resistance too. best price for a new unit is £260 from Audi dealer,

it seems to run fine when tank is full but I will monitor it when around the 1/4 mark & nearer empty, makes me think it is not the g210 sensor but the baffle housing actually running out of fuel at a certain level, or levels are wrong :confused::confused::confused:, the joys of motoring,

any tips on bleeding the system too for if and when it happens again?? the manual states basically to run the pump and remove return line at fuel injector pump but if the in tank pump doesn't pump forward how does it move the fuel up to the injector pump??

regards

Andy

[Peter D]

You mention manual so it shows the tool for removing the pump. Are you aware of the suction-jet pump set up. Regards Peter

[bagpipingandy]

Yes Peter, i recon its ok as I get past 1/2 tank ok, but when I open it up I will have a look at it to see if fuel is drawn over by it, do i need the special tool to remove the pump housing or can i make do,

regards

Andy

[Peter D]

Access is an issue without the tool. I have used a strap wrench on some retaining rings on other cars. Remember to renew the seal. The problem does not kick in until less than 1/3 of a tank and if you corner hard to the left then fuel flows across and the problem does not cut in until 1/4 of a tank. What manual do you have. ? Regards Peter

[Robnelson76]

I've been reading about the fuel level sensors as I've got what appears to be odd behaviour from mine. I have an '02 2.5 Tdi Quattro saloon. The fuel gauge when filling the tank never seems to read full (it seems to stop about 7/8 of the way up) even when the diesel pump (at the petrol station) cuts out.
The gauge seems OK from 7/8 to 1/2, with the car doing around 250 miles and the onboard computer reporting 42mpg at 70 mph. The next 1/4, so the gauge reads 1/4 full, seems to disappear over 20 to 50 miles. The mpg is still reported as 42mpg.
The gauge then seems to stay at 1/4 full for longer than expected. at no point yet has the low level light come on or have I run out of fuel.
I've read about the suction pump, baffles, fuse 28, and so on. But I haven't found anything that actually explains the system set up - is the tank in two parts? Why are there three level sensors?
Can anyone explain simply how the set up is arranged?
Thanks :-)

[bagpipingandy]

Access is an issue without the tool. I have used a strap wrench on some retaining rings on other cars. Remember to renew the seal. The problem does not kick in until less than 1/3 of a tank and if you corner hard to the left then fuel flows across and the problem does not cut in until 1/4 of a tank. What manual do you have. ? Regards Peter

Using elsawin, problem has only occured with 100 miles or less so below 1/4, I'm thinking fuel guage readings are faulty, or pump/baffle issues loosing fuel, do you think jet pump could be suspect?, out of interest I tested the pump current draw tonight, I have 1/3 tank of fuel, the draw on the pump is 3AMPS, I could hear it gurgle also, is the baffle chamber always full even with an empty tank? Or can the fuel run back out?

All info greatly appreciated

Regards
Andy

[bagpipingandy]

- is the tank in two parts? Why are there three level sensors?
Can anyone explain simply how the set up is arranged?
Thanks :-)
My take on it:
There is one fuel tank split into 2 sections for the quattro as the driveshaft runs up the centre, there are 2 levels used to work out the level in each chamber not sure exactly the 3rd ones duty but it uses a reading combined from all 3 to work out the level for the fuel guage, A pump situated in the RH side of the tanks moves fuel around from which a jet pump draws fuel from the LH side over to the RH side of the tank, the same in tank pump fills a baffle chamber in the tank from where the fuel is drawn by the Fuel injector pump,

regards

Andy

[allan_audi]

My take on it:
There is one fuel tank split into 2 sections for the quattro as the driveshaft runs up the centre, there are 2 levels used to work out the level in each chamber not sure exactly the 3rd ones duty but it uses a reading combined from all 3 to work out the level for the fuel guage, A pump situated in the RH side of the tanks moves fuel around from which a jet pump draws fuel from the LH side over to the RH side of the tank, the same in tank pump fills a baffle chamber in the tank from where the fuel is drawn by the Fuel injector pump.


Wow, I never knew there was such a complicated setup, I had a similar fuel problem with mine last year, AA came out and refilled with couple gallons and all was ok. Sounds like a problem which will worsen at some point though!!

I did find an explanation in one of the SSP guides, its for the A8 but sounds very similar (page34);

http://www.volkspage.net/technik/ssp/ssp/SSP_282_d1.pdf

Please keep us updated on your progress.

Cheers Allan.

[allan_audi]

Maybe this illustration is closer to the older A6/Allroad (Page 7), aren't the access plates under the seat?

http://www.volkspage.net/technik/ssp/ssp/SSP_206.pdf

[bagpipingandy]

Got it fixed today :approve:,
Ended up it was the 3rd fuel guage sender G237 (the one accesable from the boot) giving duff readings and making the fuel guage higher than it really was, so i was actually running out of diesel.
Using the manual there is a range of ohm readings for each level sender, I removed them one by one and measure the resistance at each limit, sender 3 was giving way off readings, I managed to remove the contacts which had some corrosion/scaling on them, clean it and all working again. checked jet pump but it was fine clearly moving fuel over from the LH to the RH. Once put back together the fuel light came on and I had zero miles left, (before it was showing 1/4 tank!!)

thanks for everyones input,

regards

Andy

[Robnelson76]

Glad you got it fixed :)

I'll have to find time to investigate mine... Full to half seems OK, half to 1/4 is wrong, and 1/4 down seems ok...

Good job we all love the cars :-)

[bagpipingandy]

when you get time best to check the resistance of the senders, let me know if you want the diagram and ohm readings for each sender at top and bottom limit.

Regards
Andy

[Robnelson76]

Thanks Andy, if appreciate that. I've PMd you my details.

[rahail240]

Hi Andy
ive just read this thread on the low fuel level sensor and I've exactly the same issues.
Since your fix has the gauge read been spot on?

any info and ohms readings would be useful for me to print out and give to my garage.
Thanks in advance.

My e mail address is rahail240@hotmail.co.uk

[bagpipingandy]

Info sent, check you e-mails,

Guage works although I still get nervous now at 40 miles left :nervous:, i check the resistance now and again, and it is still 30ohms at bottom stop,

The rear sender is easiest to check and was the problem with mine, it tends to spend most its life out of the fuel hence perhaps the corrosion. basically if you have (approx) 1/4 tank check the rear level sender resistance, accessable under boot floor check 2 sender connections, or under rear passanger seat and check the 2 connector connections (not sender). it should read 30 Ohms if sitting at the bottom stop and 91.5 Ohms top stop (removing the sender gives the benifit of testing it throught its range), the e-mail I sent has all values you may require to check all senders

regards

Andy

[wpmosc]

Does Anybody still have the Values Ohm Values for all three Sensors from Bottom and Top, Battling for a year with this already.......... ?

[rahail240]

I replaced all 3 senders with new Audi units.
Still hasn't done the job.

[wpmosc]

There is apparently still a Voltage Regulator in the Dash Cluster involved, you should get 4-5 Volt at each sender, if I remember correctly...............

[rahail240]

But if i had an inaccurate voltage reg for dash,wouldn't other gauges read inaccurately?
i just remember my capri mk1 with same fault lol, and a few gauges read wrong then.
(Just for reference, I'm not that old, its a classic car I've had for a few years!!)

[Peter D]

G210 low level 100 ohms full 430 ohms
G1 10 - 70 ohms
G169 20 - 118.5
G237 30 - 81.5 ohms

Regards Peter

[Peter D]

The 3 sensors are wired in series thus a max resistance of 270 ohms.
G210 is wired directly to the Diesel Direct Injection Control Unit and does shut the engine down to avoid wrecking the pump and filing the pipes with air. The device has a resistance of 100 ohms and if the is enough fuel then a 330 ohm resister is switched in thus 430 ohms. Regards Peter

[wpmosc]

I actually have have the Petrol (Otto) 2.7l, but according to ETKA the Diesel and Petrol are the same Sensors in the Tank, as per attached Picture. Peter can you please point out which Sensor is which ie. Right at Fuel Pump, Left and middle in the Back. Thanks....20061

[Peter D]

Exactly what model car do you have and what engine code. Regards Peter

[wpmosc]

Peter, its a 2001.5 (Basically 2002) with an ARE Engine. My Gauge shows full, then 3/4 on the Gauge is about half Tank and just before 1/4 its empty. Jet pump seems to work as filling up is consistent with Readings I get. Have changed the right Fuel Sender at the Fuel pump already and now the middle Back one, both were from eBay, but the Result was the same. Will post the Readings a bit later of those two Senders......Thanks

[ametlib]

Must admit I havent read this whole thread, but just in case someone find it interesting the ECU throws code for G 210 whenewer the baffle chamber is empty and it will not allow the engine to start before this code is gone.
Have experienced this several times when replacing/ bleeding the IP. ( could be avoided by running the transfer pump with a wire directly from battery + to fuse 28 ( or 26 ? ) )

[wpmosc]

Have tested the two I have, as they seem fine,because nothing changed when I replaced those two, its the one at the Fuel Pump right Reading 0-57 Ohms and the back middle one reading 30-107 ohms. Have VCDS and found with currently between 25-30 lts in the Tank Iget a reading of 207 Ohms and therefore 45 lts in the Tank. I have estimated the Reading of the two that are Ok at about 60 Ohms together, which then means the other one on the left is buggered.......... Have found a second hand one and ordered...... Peter thanks for your help !

[Shumadin]

G210 is the sensor in the baffle housing. I think that combination of low fuel in the reservoir and low fuel in the baffle housing both at the same time give ECU signals not to allow starting the engine in order to prevent air getting into high pressure fuel pump.

[amiram]

The ECU can tell the difference between disconnecting the G210 to the sign of a lack of fuel.