ESP Faulty when Full Steering

[Depzo]

Peugeot 308 2008
I had problems with power steering, so I had to change some parts on the steering wheel.
After changing it, when steering full left or right I get a message ESP System Faulty and the ESP turns off.
I took it to the mechanic and had to replace the COMM2000 unit (the unit was not a new one), but the ESP System Faulty was still present when full steering.
Then they told me I had to center the steering wheel, did that problem was still there. Afterward, they told me that the rear beam was at fault and that was causing it.
Took it to another service where they told me the COMM2000 is the problem.

The problem is only when full Steering.

What can be the cause of this? Can it be the rear beam or is it something else?

[wheeler]

Was the steering angle sensor re calibrated after replacing the Comms unit? This should also be done after any steering angle adjustments.

[Depzo]

Was the steering angle sensor re calibrated after replacing the Comms unit? This should also be done after any steering angle adjustments.

I'm not sure. The first time the COMM was not replaced, other parts were for the Power Steering. Is there something else that can cause that problem when changing parts on a steering wheel?
Where should I take the car for that, to a mechanic or an auto electrician?

[wheeler]

Where should I take the car for that, to a mechanic or an auto electrician?

Anyone with decent professional diagnostic equipment should be able to do this.