Q7 2016 Coolant Pump C Stuck

Hi all this is my first thread. I have a 2016 Q7 3.0l diesel and the engine check light has come on intermittently but is now on all the time. I have a fault finder reader and the message I receive is 'Coolant pump C stuck' with the code P26F800. Issue is Audi don't recognise this code or which pump is Coolant Pump C which could also mean 3. which pump is this I believe there are 3 one main pump and 2 additional pumps. has anyone seen or had this issue?

Can anyone help thank you

John