This has been bugging me for a few months now and I have not got my VCDS cable linked to my netbook yet so not read any codes.

Here are the symptoms.

2005 Elegance 1.9tdi Octavia.

When the fuel is low, the Engine light comes on.

What can be causing this?

any one?

What codes do you get when you scan?

Does it have a water in fuel sensor?

worn / faulty injectors can give you that symptom as the pressure on the return drops and the rail tries to protect the injector by forcing a limp mode...would be interesting to see the DTC's for the MIL!

How low your you talking about with the fuel, are you letting it get into red?

fuel light turns on with 70 miles left and then the engine light comes on.

Will scan it later for codes.

It could just be water in the tank coming through. How often do you run it into the red?

I wouldn't make a habit of it as it'll do the engine no good at all.

Only ever run until the fuel light comes on. Never go to empty or anything.

Have you had a new fuel filter recently?

If not, then you could be finding that the lower fuel amount, combined with a partly blocked and water filled filter is making a mess of things.

Had a full 2nd Variable service before I bought it.

Car needs the fault codes reading to see what is putting the light on before you go any further.

Had a full 2nd Variable service before I bought it.

That won't have included the fuel filter.

That would be my first port of call.