Trip Computer Mileage does not Go Up, and Fuel Gauge Faulty

[Lion Heart]

Hi guys

I'm looking at buying a A6 (C6 2.0 TDI diesel S Line). I've found one that I really like the look of, which is sensible money but has a fault:

On the dash the trip computer mileage does not rise as you drive, but the normal mileage does.

Additionally, the fuel always shows as empty.

I assume these are most likely linked??

Why would mileage rise, but not the trip computer???

I'd like to know what I'm most likely facing before I take the plunge and buy it.

Any help very welcome!

[niall campbell]

could be a fuse or the fuel sender unit is faulty

price a replacement fitted to the car and take that off the asking price

[Lion Heart]

Yes, my first thought was fuel sender...

BUT why would that cause the miles on the trip computer not to go up???

[AT.]

BUT why would that cause the miles on the trip computer not to go up???

Just a clue: The trip computer's main duty is to calculate the fuel usage/mileage ratio, and therefore it collects the data from the fuel system and from the distance calculator. When there is no fuel information (please refer: the fuel is always off, it means zero fuel consumption!), then there will be a divide/zero calculation, or at least an infinite mileage/distance value, and IMHO in this case the MMI will drop the information in this case as useless/unuseable value, and therefore will refer to no fuel consumption, and no travelled mileage. Of course, it's for the travel data only, it will not harm the normal distance calculator in the MMI.

[MarkTM]

Lion, I don't think the fuel gauge reading zero and trip not working are linked, when I had the zero fuel gauge issue on mine it was the sender balancer in my quattro, however no issues with the trip.

Try resetting with the button under the right hand stalk, if no joy then get it scanned with VCDS....this can cost between £40-£100 a time, personally I'd not buy it and as the seller to get it scanned and pay for the fix.

If you add your location to your posts it might help, I have VCDS but have no idea where you are?

[Lion Heart]

Hi Guys

Ut-oh... We have a case of conflicting information - can anyone else help shed some light on this??

What AT says seems to make sense, but then MarkTM had an issue where this did not occur. If AT is correct then (maybe?) whenever the fuel would read 0 then the trip would ALWAYS fail as well?

Any more help welcome!!

I actually have VCDS myself. The problem is the car is over 6 hours away and so if I'm going to make the journey then I'm going to buy it. I normally wouldn't take a car over that distance with this fault, but the price is good, and the car has the spec I want and looks how I want. So really like the car, just need some educated guesses as to the most likely issue.

Any more info welcome!!!

[AT.]

I normally wouldn't take a car over that distance with this fault, but the price is good, and the car has the spec I want and looks how I want.

"If something sounds too good to be true, it probably is."

This fault can be an easy thing, but can be an expensive MMI problem too.

If you have a VCDS, why don't you check for the error codes? If you share the error code here, maybe there will be a professional to figure out what's the exact problem. Also I think, it could be a good idea to go into an Audi service, and ask to check for this problem. A price offer for the repairs is almost free, but in this case you can be sure what will you purchase for your money.

Maybe the price is so good because the seller already knows the price for the necessary repairs. Usually, if a car have only real minor problems, then the seller repairs these itself before the selling, because it's far easier to sell a car without any problem, than to try to sell it with an explanation why the seller was not interested to repair the failures for himself.

[Lion Heart]

"If you have a VCDS, why don't you check for the error codes? If you share the error code here, maybe there will be a professional to figure out what's the exact problem. Also I think, it could be a good idea to go into an Audi service, and ask to check for this problem. A price offer for the repairs is almost free, but in this case you can be sure what will you purchase for your money.

Maybe the price is so good because the seller already knows the price for the necessary repairs. Usually, if a car have only real minor problems, then the seller repairs these itself before the selling, because it's far easier to sell a car without any problem, than to try to sell it with an explanation why the seller was not interested to repair the failures for himself.

I can't scan it because the car is over 6 hours away, so I can't just pop in. Basically, if I make the journey I intend to buy the car. Hence trying to figure out the most likely issue prior to making the decision.

It's a car local to the garage taken in Part Exchange and being cleared. They are not interested in repairing it up or doing any tarting up such as refurbing the wheels etc - they are just clearing it as-is.

This does not mean it's a bad car, but it could be (of course) if this issue is actually major.

I was hoping someone here may have experienced the exact same issue, or have a decent idea to the likely cause...

Having the trip computer and fuel gauge linked to calculate mpg etc makes sense, but on the other hand looking at most reports (as above) of people with failed fuel gauge's - they don't seem to mention the trip computer failure. If they were linked then you would think the trip computer would fail in every instance of a fuel gauge failure?

[AT.]

If they were linked then you would think the trip computer would fail in every instance of a fuel gauge failure?

No, I don't think it's a mandatory thing, it's only a plausible explanation. What I think is, that no one will be able to give you the proper answer without the MMI error codes

[Lion Heart]

Yes, that's a possibility. But if someone here has come across the issue before (and resolved it hopefully) they should have a good idea of the nature of the issue...

Agree that logic would dictate that it's more likely that they are linked in some way rather than two separate unrelated issues.

Anyone reading this know of the fuel gauge and trip computer both not working on one of these?