I have a P122C code on my 2009 X35D which points to a NOX sensor short circuit.

Since there are two sensors, does anyone have a clue which might be the problem? I'd normally replace both but they're $600 per sensor. (ouch)

Would the IPNA software be able to isolate this better than a generic ODB2 reader? I don't have a windows laptop to install the software but if it will isolate it, I'll be money ahead.

thanks.