UPDATE - For what its worth, this is where I'm at......
Had the car serviced in Sept last year by Arnold Clark, but decided to poke around a little on my own today.
Started with the air filter and WOW is all I can say. On opening up the air box there was a fairly hefty amount of leaves / debris / dust etc in there and the filter was awful!!!
The car has probably only done around maybe 5k in that time, if that and mostly motorway, and always driven easily.
Anyway, I removed the filter and thoroughly cleaned the housing removing all the crud and replaced with a new filter.
I also added some Redex to the fuel to help in cleaning the injectors as well as some STP additive into the oil.
Its early days, but after more than a few miles nd several stop / start / stop cycles the warning light has failed to reappear so far
Anyhow, for the moment its running quieter, sweeter and much more smoothly than before with no "EMISSIONS WORKSHOP" warning light........here's hoping.
If there's any change I'll repost of course
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Re: emssions workshop dash message
Update >>>> I seem to have the problem resolved with some excellent help from PeteK on the EGR vlave.......Please see link below to the thread in question which you may find useful if you're looking at this thread.
https://www.vwaudiforum.co.uk/forum/s...-valve-removal
Good luck
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Re: emssions workshop dash message
Further update >>>> It seems that cleaning the EGR valve on this occasion did not fix the issue as it came back and the dash warning light intermittently appeared, so back to square one!
I certainly believe that cleaning the EGR valve was helpful and a worthwhile exercise for future reference.
Not having VAG-COM I turned to the next most likely culprit ( in fact probably what I should have done forst tbh ) and that was the temp coolant sensor. I got it off
Ebay for around £6.00 and that included the O ring and the horseshoe retaining clip.
Just outta interest I called the dealer who wanted £34 incl of Vat but that was for the sensor only. The O ring was a further £1.34 + the clip wass extra too.
Anyhow the temp sensor was changed by a local mechanic friend of mine......Its located just under the EGR valve but is kinda hard to access.....All in took around 30 mins and £10
Total for the fix was £16.00
I have a funny feeling that the dealership would have been in the region of £250 - £300 to diagnose, then supply + fit incl of labour + vat so I'm well chuffed
As stated, this may or may not be your problem, but your symptoms sound exactly the same as I experienced.
Turns out a £6 part off Ebay and £10 for a local mechanic to install and the problem has been resolved, around 2-3 weeks now I guess and no issues whatsoever................Its up to you, but if you can't get any codes it might be worth a try and a possible cheap fix
Either way, good luck....
Jim 
