Opel Astra J 1.4 140KM: Understanding & Resolving Error Codes P0697 & P06A3 - Sensor Voltage Issues

Hello.
For a month now, I have been a happy owner of the Opel Astra J 1.4 140KM.
After connecting to the computer, there are errors that cannot be cleared:
- P0697 - C sensor reference voltage - open circuit.
- P06A3 - Open circuit, voltage reference sensor electrical current D.

The car starts, drives without any problems, no indicator lights, but there are errors :(

Can anyone tell what he means?
Maybe some sensor is dirty?

Greetings.

Due to the complexity of the fault codes, I think you will not be able to handle it yourself because the fault can be in many places, but it concerns (P0697 e.g.) the 5V power supply (sensors, wires worn / shorted, or the ECM itself). That is why it is impossible to tell here clearly how to remove the above-mentioned errors, because it is tedious to look for everything in turn ... Scheme in hand, universal meter (enough), diagnoscope and ... forward Check engine will light up sooner or later anyway because it doesn't always have to light up right away ...

OK thanks;
Or maybe you will tell us where to start, maybe there are places to look first.
Maybe cables like rubbing in this model?
Maybe some sensor causes this error?

Thanks in advance for the hint.

I checked all the connectors, treated with WD and so far for 2 months there have been no errors.