do the codes return after you reset the adaptation? and it's 221 and not 121? 121 is automatic mass meter, 221 i've never seen.

221 means the car is lean. 231 is a reaction to what's causing 221. check for vacuum and exhaust leaks. it could also be low fuel pressure and/or a bad amm. i've got the test adapter to lh car and i've not seen it in generic fuel pressure test kits. not sure how you can test it. it's a tee fitting that screws onto the rail where the fuel comes from the tank.

i've never had to chase a 221, so i can't give you a direction. volvo is pretty vague about mixture control testing. 231/232 i've always regarded as a nuisance after chasing it on a few cars and not finding the cause. good luck, chuck.