2000 v70xc To MAF (again) or not to MAF?

[albertoVO5]

Neil and Abscate, thanks again.
I will get the pipe back on securely and go from there; my concern is that the pipe popping off may have acted as a pressure relief to an overboost. While I've done plenty of work on cars over the years, this is the my 1st involving a turbo.
The 'pop' I heard was just starting up a moderate incline at 20-25mph - would that be a typical time for an overboost? I hate to sound simplistic, but how does one check for overboost? Is there a basic check that can be done, then proceed on to Manifold Pressure gauge etc? (which I find difficult to follow - not for the check, but ID'ing the components involved under the hood vs. the diagram.
Would a P1238 code (the only one that shows, listed on my reader as 'Manufacturer Ctrl, Fuel air metering') be in the ballpark for an overboost?

Bill