I have a passat, buti t's petrol and 2002, but do know quite abit about the passats.
First of all, I'd check the oil for sure as it can throw this error. Check then check again with the oil when the engine is cold as this will be the most accurate.
I know you said it seems common but I've just checked the recall website and nothing about it (VW are usually good, as they want to keep up their reputation)
For a quicker 'fix' if it was just a sporadic fart in the system disconnect the battery for 10 mins to plug back in and see if the issue re-occurs, if it does then you know there is a problem and not just a one off)
So I'd try that, then if possible get it booked in for some diagnostics at VW (yes it's more money, but the tools they have are designed for VW's!)
Or if you don't fancy a diagnostic just yet register at http://www.ukpassats.co.uk
got loads of very helpful people there