Dpf / Exhaust Pressure sensors and wiring

Hi, So I have a wiring fault within the dpf and exhaust pressure sensor area. I’ll be sorting it tomorrow when light. However can anyone tell me

1. If the part numbers 03L906051 should be fitted to my car or should it have the 04L906051 parts on as it’s a 2017 and other things in the car have ‘04L’ part numbers? (Assuming they may have been replaced previous to my ownership and curious)

2. In the picture what is wire 3 connected to? I hear a clicking (solenoid type) when moving the loom connected but didn’t see what it was. I don’t believe it’ll be the pressure sensors 1 and 2 as they aren’t solenoids are they?

Thanks

Rob