CAT 336E Exhaust System Question

[ms0115]

CAT 336E LH Hybrid
Serial # - CAT0336ECRZA00244

Fault Code 3409, FMI 5, Count 1
Engine exhaust manifold bank 1 flow balance valve solenoid.

Can someone please explain to me what this code is, the location and how to test for it? Thanks for any help.

 

[Nige]

Here's what the book says............ it looks like it's going to need ET.