Fuel warning light

johnyfartbox

A2OC Donor
United-Kingdom
As in title............new car picked up this afternoon and turned ignition on, fuel buzzer sonded and warning fuel pump appeared.........but half a tank showing on gauge.........any ideas chaps?
 
As in title............new car picked up this afternoon and turned ignition on, fuel buzzer sonded and warning fuel pump appeared.........but half a tank showing on gauge.........any ideas chaps?

Has it done it since? The instrument cluster monitors the resistance of a float in the fuel tank in order to establish how much fuel there is and whether a refill is needed. Resistance changes as the fuel level changes. If there's a bit of dirt on the electrical tracks of the float, a sudden increase in electrical resistance can occur despite there being plenty of fuel, causing the fuel warning to appear.

Cheers,

Tom
 
Thank you Timmus for the reply. The guys at the showroom knew about it and I think are trying to fob me off with the excuse saying it must have been programmed at some stage. I had an idea it was a fault but wasn't to sure so thought I would ask here. The beep sounds as soon as the ignition is switched on. Is there a fix for this problem Timmus??

Regards.
John.
 
Hmmm, curious. Now that you've said it happens every time you turn on the ignition, I'm doubtful that the theory I've written above applies to your case.

So, just to be clear, no matter where the fuel gauge is pointing, the beep sounds?
Does the gauge otherwise appear to work perfectly? Does it give a meaningful indication of fuel left in the tank?

Cheers,

Tom
 
It does indeed sound every time the ignition is turned on...........When the car was picked up there was exactly half a tank according to the needle and it beeped............now ive done a few miles in it the needle has dropped to just before the quarter point. I havnt worked out the on board computer as yet, not had much time but im sure there is a reading saying how many KM there is left in the tank ...............sorry if im not being clear.
 
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now ive done a few miles in it the needle has dropped to just before the quarter point.

Ah, ok. I'd assumed you'd been driving it for a few tanks worth of fuel. In which case, my original theory could still be valid.
Take it to the fuel station and fill it up. Once the low-fuel beep has gone off, the cluster needs to see an increase in fuel level before it stops pestering you about needing fuel. There may still be a problem, but we can't make any further headway until I know what happens after a fill-up.

Cheers,

Tom
 
Hi Tom.
Filled her up to the brim tonight , took £32.74, the needle was just over a quarter full and is now hard against the full needle.
Buzzer didnt sound and fuel pump symbol not lit when ignition switched on..

£1.20.9 per litre...................27.08 litres.

Im assuming I have a 42 Lt tank and assuming I had paid £1.21 it would have cost me £50.83 to fill from empty so there must have approx £18.00 of fuel in the tank which would account for the needle reading in between half and quarter.

So im guessing the needle reading is correct and the buzzer is just sounding on half tank.......................

Regards.
John.
 
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will be interesting to see if it start to a warn about low fuel at about 1/2 a tank.
With any luck filling the tank will have exercised the fuel sender and hopefully removed any muck that 'may' have cause it to provide a low fuel reading which will have triggered the beeping.
My understanding is that it will beep every time you key the ignition until the instrument cluster sees a notable amount of extra fuel in the tank, at that point it will stop beeping
I think Timmus theory is that the tank sender unit some how sent a low fuel reading (which triggered the beep), but then didn't see extra fuel in the tank to reset the beeping.

I one had near exactly the same think on my Ford Focus CC, it simply did not see the full tank of fuel I had just put in it, the low fuel light /warning was on for 450 miles until I next filled up, even though the fuel gauge was reading the tank correctly. On the next fill up the warning cleared and all was back to normal. it happened once in 5 years of ownership (about 2 years ago) so hopefully this is not your 3rd bit of bad luck and will stay clear until your are entering the red zone
I must say that the guys at Audi must have been really worried about running out of fuel (understandable when it uses so little) but every time the damn warning buzzer goes off I near s**t my self, it is anything but subtle !!!
 
Thanks for the reply buddy.
Yes, filling it up has put my mind at rest regarding if there was enough fuel in it............I will now see what happens all though it may take a while......the wife is using it all next week and the week after and she only does 12 miles a day.........pfffft.
Then again ,just might have a run out in it over the weekend and visit a rich aunt who is unwell at the moment in Knaresborough.
Must admit, it scares the bejaysus out of us both when the buzzer goes off.............strangley, the buzzer on the blue one (RIP) was no where near as loud.
 
Ok lads.

Yesterday the gauge reached just a smidjin under the half mark and the buzzer sounded and the warning light came on..........246 miles from full to reach that mark. So its either live with it or do some more research to find out whats up with it.
 
with 246 miles gone to half way ish id say its possibly reading wrong too, i usually get between 300 and 350miles down to the warning beep, which is half of the quarter tank, on the red, might be worth removing and checking the float mechanism next time you get time and lower on fuel as easily removed from the tank, maybe it just needs manually cleaning of the brass contacts on the end of the float lever
 
Ok lads.

Yesterday the gauge reached just a smidjin under the half mark and the buzzer sounded and the warning light came on..........246 miles from full to reach that mark. So its either live with it or do some more research to find out whats up with it.

Has the instrument cluster been worked on recently.

It really could be that the pointer has been put back in the wrong reading? But I would guess that when you switch off the needle wouldn't return to exactly zero.

So as Jigsaw has mentioned it may well be the sender. DO you have access to one you can swap to eliminate that as the cause?

Steve B
 
(Has the instrument cluster been worked on recently?)............ Not to my knowledge

I could try the sender from the cat C car I spose. Is it a pig off a job or quite simple?
 
(Has the instrument cluster been worked on recently?)............ Not to my knowledge

I could try the sender from the cat C car I spose. Is it a pig off a job or quite simple?

It should nto be too bad, just remove the back seat undo the large disc and it is under there. Are both cars a similar age? because the tanks and senders were changed (some time in 2002 I believe) The tank is smaller in the earlier cars and I think the sender works the other way around (happy to be corrected on that)

Steve B
 
It should nto be too bad, just remove the back seat undo the large disc and it is under there. Are both cars a similar age? because the tanks and senders were changed (some time in 2002 I believe) The tank is smaller in the earlier cars and I think the sender works the other way around (happy to be corrected on that)

Steve B

you are correct on both counts Steve :)
 
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