if you code it out, your towbar will cease to work.
then when you actually want to use it, youll have an issue.
these retractable towbars are notoriously problematic.
even if its retracted it might not be all the way in, telling your dedicated towbar sensor its not secured, generating the error.
Theres a towbar reset procedure that used to work on my F10 to reset it, and it will then recalibrate by opening and closing, then opening again.
the light then goes green inside the boot, and you can close it fully.
I am not sure if G20s have this, but its something you can google.
the other thing that works is opening it- let it do its thing, then wait a few seconds - you shouldnt hear the motor.
then press retract - let it start closing and push it (help it) with your hand all the way till its closed completely. you will know its locked when you dont hear the motor.
Then NEVER open it again unless you need to tow.