What does Volvo error code P0172 mean and how should it be attended to?

Code P0172 indicates a long term, lean or rich fuel trim error. In this case according to the OBD Scanner it is too rich. Possible causes could be a faulty mass air flow sensor or one which has not been correctly calibrated. If the maf was recently changed it may be that the computer needs to be reset and is still adapted to the old maf.

One thing which could be tried is to clear the codes and disconnect the battery. Reconnect it after a gap of 10 minutes. By doing this all modules should be cleared of their adoptive values.

 

If you are sure it is rich, you need to figure out if its getting too much fuel, or not enough air. Most cases, not enough air. This can be due to an intake leak, a dirty throttle body, bad TCV, and a couple other things. I would check the data on the fuel system, tcv duty, throttle body angle values, etc and see what looks out of sorts. The DTCs always point to the MAF and people constantly replace these when they don't need to. However, it doesnt hurt to keep it clean using a MAF cleaner spray from the parts store.

Fuel trim issues are never fun to dive into.

It also helps to know what kind of car you have

 

Generally, the MAF isn't a common failure. It is usually replaced as a guess. If the MAF really is the problem and you replace it, the fuel trim will correct itself over time- there is no requirement to calibrate anything.