engine service light comes on and slows down
 

I have an s60 diesel 2002 d5 common rail diesel, great car apart from this one
niggle, occassionally on acceleration in 4th gear mainly, the service light comes on and the revs are reduced by the control system, no amount of accelerator helps, again turn off ignition and away car goes, I have changed rpm sensor, which my ppc diagnostic said, I have disconnected the vacuum pipe and blocked it to the engine suspension units I have changed the vacuum pump,
any ideas please

I have the same problem with my S60 D5 2003. Did you get sorted yours? If so, what a problem was?

I cant be more specific, but i have read a post where the big turbo vacuum pipe situated on top of the engine becomes degraded and collapses when subjected to hard acceleration.From what i have read it is not a big nor expensive job. If i come across the post i will post ,if you know what i mean.

there are many things which can cause this , you need to get the volvo codes read from the ECU and let that be a guide ...