Car Owners Hub UK - Built by Drivers, for Drivers

My 2000 W210 E320 CDI (OM613) is in need of some guidance.

An EPC/engine warning light has come on, and the vehicle has entered limp mode all of a sudden. There is a dramatic decrease in power.

Here are the current and stored faults that I've detected after scanning it:
The electronic switchover valve is part number P1622-008. The P1403-008 is an open circuit for the recirculation of exhaust gas.
Open Circuit for Charge Pressure Control (P1470-008)
P1189-008 - Open Circuit for the Inlet Port Shutoff
The MAF signal voltage is too low (P0100-001).

The problems persist even after I replaced the K40 relay/module with a known good unit.

The fact that the EGR, charge pressure control, inlet port shutoff, and Y75 all have "open circuit" faults at the same time is strange to me; it makes me question whether there's a shared problem with the power supply, fuses, or wiring instead of numerous broken parts.

Is this a common combination of codes on OM613s?

Is there any guidance available regarding:
Which fuses are used to power these solenoids and valves?
Points of common failure in wiring?
Is it possible that the other faults caused the MAF fault?

Any assistance or suggestions would be greatly valued.

Wiring loom problems could be plaguing a 26-year-old vehicle. Perhaps an indi could be of assistance to you.

Take a look at your fuses; all of mine are on the same fuel in my vehicle (212). Those codes were caused by it blowing on my end, which is my fault.

Many issues can arise due to low voltage. Take a look at it after swapping out the battery.