The Motronic 7.2 DME Diagnostics manual lists a number of possible causes for P1411 - Secondary air injection system, bank 2.
- A bad secondary air injection pump
restricted air supply lines
electronic changeover valve not functioning
air changeover valve not functioning
vacuum leaks
wiring harness
relay
DME control module
It also calls for a testing procedure using the PIWIS or PST2 tester and calls for specific air temperature and air mass values.
I suspect that since it's isolated to Bank 2, it's probably vacuum leaks or the MAF, at least that's where I'd start. The other causes call for replacement of components and need the tester to isolate them.