The dashboard of my 2007 2.5T lit up, engine management, dynamic stability and cruise control all on, so I get home, plug in the OBD and get P0410, secondary air. Some time on the web gives me information and advice and suggests that the first things to check are the fuse and relay but they're not identified in the manual. My local Subaru agent explained that when it identifies a fault the ECU automatically shuts down driver aids, so beyond no ABS or cruise control the car is safe to drive which is reassuring. Unfortunately they want £220 + VAT just to locate the fault so any suggestions as to how I can do this myself would be very welcome. Looking down the line a little, by groping below the intercooler I've located one of the valves in the system, I'm guessing the second one is down there somewhere and that if I have to lift the intercooler out to get to them I'll need to drain the cooling system, yes?

Remove and block and program them out of the ECU, my specialist indy did ours, there is a danger of the bolts sheering off so be aware it could rarely turn into a bigger job than one might hope.

Thanks for the suggestion, it's definitely an option but I haven't found anyone yet who'll do it for less than £300 which is a struggle. Half an hour under the bonnet today revealed a non-functioning pump, to replace that could be a used OE unit or a chinese copy from ebay. Thank goodness the car is still usable!