2 Faults Found on my 2001 Octy vRS:

17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)

P1297 - 35-00 - -

16514 - P0130 O2 Sensor Circ.,Bank1-Sensor1 Malfunction

(checked codes against the sticky thread on here to get description for the 16514)

Now the warning light came on last Saturday while pootling along in 5th gear with my foot off the accelerator, it juddered a bit and I changed down a gear and pulled away gently. I drove home with the only noticeable problem being the car juddering while idling at traffic lights. It was left over night and started the next day and has been right as rain ever since so assuming its reset itself and the problem hasn't returned. On that basis I reset the codes tonight to get rid of the warning light.

I take it if the problem happens again the lights will come back on and that it doesn't need to go to the dealership unless the warning light returns?

Oh and I used an ebay cable from Hong Kong with the trial version of the 409 software on my old laptop and it worked brilliantly, the cable fitted perfectly and had no issues with communication with the port, fantastic for £13!

The 17705 is quite well documented on this site and it could be a number of things. I would have thought that the light came on due to the 16514, it refers to the first lambda probe. It is possible that on fuelling for the air that was measured at the intake and then calculating the air entering the engine taking the turbo boost into account, the pressure drop may have caught it unaware and gave the lambda sensor a reading that was so low or high that the management sytem thought it was malfunctioning. The management sytem shut it down and used default reading for it bringing the light on and giving the uneven idle.

Thank you for your reply. Thats good to know its a code thats been seen a fair bit. The car has been fine and no sign of the warning lights coming back on so looks like resetting the codes was OK to do and that it was just an issue caused by too low revs in fifth while pootling around country roads. There has certainly been no idling problems since leaving it over night after it happened