On a 20212 LR2 3.2 L V6 USA version could a leaking gasket on the vacuum pump be causing these codes to show up. appears to be some oil leaking in this area. A previous smoke test showed no other vacuum leaks.
Thanks in advance

 

The leaking gasket on the vacuum pump is a pattern problem on this vehicle. So common that they make a seal rebuild kit for it - Volvo 31401556. You can find lower priced aftermarket versions of this kit on Amazon and eBay. But if you go that route, then I suggest you compare the aftermarket kit photo against the genuine Volvo kit to ensure you're getting the correct items.

The vacuum pump leak is typically minimal with oil seeping around the cover. It's possible but doubtful the 171/174 codes are caused by the leaking vacuum pump, unless it's a real gusher.

Suggest you check the fuel trims to collect more info. From my AI friend:

A classic vacuum‑leak signature is high positive trims at idle that improve toward normal as RPM/load increases.
To diagnose, warm up the engine and watch STFT and LTFT at idle on both banks.
If one bank shows much higher positive LTFT than the other (for example Bank 1 +20%, Bank 2 +2%), then suspect a bank‑specific leak on that side (e.g., intake manifold gasket). If both banks show about the same high level, then the leak is a component common to both sides (e.g., air filter housing or air intake hose).

 

AI might be confused on one point, a leaky filter housing isn't going to affect air/fuel ratio, a leak has to be downstream of the airflow sensor to affect trims. A leaky filter housing might let in some dust.

 

Agreed generally. The couple of exceptions to this would be if a leaking box resulted in air flow bypassing the filter and contaminating the MAF sensor with dust/dirt, as you said, throwing off the measurement. This happened to me and was corrected by cleaning the MAF element and reseating the box. This fix cost me $8 for a can of MAF spray cleaner. I discussed with my LR dealer afterwards and he told me their shop would have replaced the sensor for hundreds of dollars ... they don't clean stuff.

The other exception is if the leak is so large that it creates air turbulence which causes an erratic MAF sensor measurement.