S40 (New) Engine D5 : Engine Fault Message?

[VenomS40]

I recently took my 2009 S40 D5 for a cam belt change and the garage told me that their fault reader was showing that I had a fault code on the system.

This problems seem to come and go without any kind of pattern, sometimes the engine will rev out freely and then some times it feels as thought it doesn't want to rev past 3k RPM.

The information screen shows a message saying 'engine system service required' or something along those lines. This message has no ties with the intermittent issue with the engine not wanting to rev past 3k on occasions?

It all seems just a little random and nothing ties in to one another? The garage didn't clear the code but put on the invoice 'catalyser temp valve' and said this was the issue and if I wanted to rebook the car back in to have this valve changed?

Can anyone shed some light on this or give some advice as to what's going on or if this part even exists as I cant find anything in the search function of the forum?

[cheshired5]

You need a member with Dice or other high end diagnostics as any number of things can cause this issue.
Mine was a faulty MAF but I guess it depends on how much you trust your garage and whether they'll guarantee their suggestion as being the solution.
It's easy for them to guess when you're the one paying.

[Volvo master tech]

If the car is showing a dtc for a catalyser temp or dpf temp sensor this will definitely cause a lack of power /limp home ask for the detail of the fault code as these sensors when faulty default to 1002'c that should be in the frozen values .