Rover owners: IPK not recognized afther disconnection

Please , some help about IPK from a diesel rover 75 CDT building year 2000 .
I have pul out the IPK very gentle , correct disconnect the 2 connectors , first the white onen then the black one.
Afther disconnecting the IPK , i have only clean the glas on the backsite , and dry ofcourse before putting in .

I am very in known about elektronic hardware and i have NOT open it to the IPK print pcb.

I connect and place the IPK back and put on the contact whith the key , ready for starting , fuel is empty , RMP meter is not working , no speedo meter working , no temputure working , the smal lcd whith km is working and test service 2.0 is olso working and al the meters arre working and lights LED's .

So wath i see is no communication wth the main computer i thingk or must it reset ?

Making the computer untherstanding that the IPK must again recognized and must communicate whith service TOAF in garage whith an service code from rover ?

Someone the same problem ?

Battery was not disconnected , and may no problem or so do ?

Great regards and tanks allready !!

Roant