[I need coffee]

2011 Murano Check engine light on. Code P0101 Mass Flow Sensor - cleaned, light still on. Replaced, light off for 20-30 miles, light back on. Any suggestions?

If you still have the original OEM MAF sensor you should reinstall it as it's likely better than the new aftermarket part that was installed.

As stated previously, this code is rarely caused by a bad MAF sensor. More often it's caused by a vacuum leak. Dirty throttle body is another potential cause among other things. Search these forums for that code as there is extensive discussion about it.

 

[I need coffee]

I am being told by what appears to be a reputable shop, hat I need to take my car to Nissan to have software updated before going further with the P0101 code. Anyone???

I would expect there to be a TSB if a software defect was causing a trouble code, but I can't find one for the 2nd generation related to that code (...there is for the 3rd generation though). I suspect the shop is trying to cover all bases so they don't chase their tails troubleshooting something that's a software glitch. If your ECM firmware is not up-to-date then it would be a good idea to update it. Nissan will charge you, of course (...they'll probably charge you just to verify the software version).