From reading the forums this seems to be pretty common fault with the Fabia, my pas light came on in December and after phoning a dealer and asking advice, I topped up the fluid level in the battery and re-charged it (the battery was new in January last year), the fault light stayed off until last sunday.

I pulled over and switched the engine off, when I restarted the engine the light stayed off and has done so until yesterday, when I did the same again, so far it is still off. The steering sometimes goes heavy or light.

I have seen on posts error codes, what do I need to do to find out what error codes my car may have?, I do a lot of motorway driving and want to get this problem fixed ASAP.

There seem to be a lot of power steering threads just lately, but to some extent you've hit the nail on the head about the fault codes. You can buy a VAG-COM lead and download the shareware if you have a laptop, or you can get a hand-held scanner for GBP30 upwards. If you don't reckon on using either much, though, pretty much any garage will do a fault scan - but the price can vary!!!

Do you have any other symptoms in the absence of any fault codes? Does the weight of the steering change when you're doing anything in particular, or just at random?

I finally had a diagnostic check on my car and this is what came up "08 000 816 sensor for power steering G - 250" . Any ideas?.

The way to go is the Ross Tech Wiki

DTC 00816

It would suggest it's your sensor at fault, rather than the pump, which is a credible DIY job for anyone with access to nothing more than an Allen key and a couple of axle stands...

http://www.fabia-vrs.com/technical/pas_sensor.html