Check engine light ON (Emission service) after timing belt change. OBD II scan tool cannot read any code, but can reset the light. Afrter the reset: rough idle until check engine light comes on again after couple of seconds (10 or so). Ones the check engine light is back on the car is running OK.

Visit some auto parts stores that loan code readers, if your reader can clear codes, then it should also display them.

I wonder if it just might be that the tensioner was not tight enough and the tbelt is now off by 1 tooth?
--
My name is Klaus and I am a Volvoholic.

Hi Klaus,
I’m George. I was able to read the ODB II code: P0011 with different scanner. This corresponds to Volvo code ECM-644A*. The timing reported by the ODBII scanner is 5 degrees advance at idle. The Volvo spec is 10+/-2. Most likely I’ve installed the belt 1 tooth off. I doubt the belt slipped. Do you know how many teeth are on the crankshaft sprocket, or how much degree is one tooth?
Thanks

The VVT engines are quite picky :) One tooth off is all it takes. Remember to turn the crank past TDC when you are aligning the marks and then back to TDC, that takes the pressure off the cams.

Do not be afraid to run the engine this way, the code is a warning. And double check the tensioner setting while you are in there.
--
My name is Klaus and I am a Volvoholic.

As Klaus suspected, the timing belt alignment was 1 tooth off. Looks like I didn’t follow rule to go 90degree past TDC. Reinstalled the belt, reset the MIL, took 400miles trip – everything’s OK now :-)
Thanks, Klaus!