My PD140, 55 plate, 63k miles, has dropped into limp mode a couple of times this week. Stopping and re-starting the engine clears the problem for a few days.

VCDS shows 16618 as the only fault code, engine management light never came on though.

I've only had the car a month so am gutted! Any ideas on what course of action to take?

I had a look under the bonnet and all hoses appear connected and in good condition.

P0234 was a fault code I had on my old Mk1 TDI a few years back. It was a overboost of the turbo caused by the sticking vanes. The engine management light came on eventually. There are a few threads around on this problem and if it is the sticking vanes they can be stripped and cleaned.

I thought that problem had been resolved with the PD140/PD170?