Check the coolant level. My 2000 V40 threw that code and I think the cause was insufficient coolant after a water pump change. Of course I didn't figure that out until after I changed the thermostat and the old one functioned normally.

I bought a Stant 48639 thermostat which turned out to be a Wahler thermostat made in Germany in a Stant box.

 

I just ordered an OEM thermostat (#271664) for mine - it appears to be 90degC which converts to 194F.

 

My local indy shop wanted $1200 for just the timing belt replace, not that I took them up on it. I don't think they wanted the job.

Did the shop have a Volvo Dice VIDA scanner? If not, you may want to set one up yourself. There may be some Volvo codes lurking in the ECM that would set you on the right track for the low power problem.

 

Thanks for the tips everyone... you've all been very helpful in fixing this problem.

The CEL turned off yesterday... as soon as I changed the thermostat it seems that the power increased... maybe this was just perceived... I don't know. The new gas seems to have helped too.

Of course I've just ordered $100 worth of parts (radiator temp sensor, air filter, and boost solenoid)! Oh well... I'll probably replace them all just to put the new parts on - preventative maintenance.

 

Get yourself a cheap OBDII reader. I think they can be found for $25 on Amazon. Nothing fancy but you can read the codes & clear them yourself. It will pay for itself the first time you use it.