Figo control unit communication error

Control unit communication errors in Fords of that era often stem from faulty connections. Have you checked the cable and plug connections to the control module itself? A loose or corroded connection could easily cause those symptoms.

When you say "control module," are you referring to the ECU, or is there another module I should be focusing on specifically related to the cooling system? Any pointers on where to find the relevant wiring diagrams?

Yes, start with the ECU connections, but also check the coolant fan control module. Given the overheating and coolant issues, a fault there could trigger the communication error due to the ECU attempting to compensate. Wiring diagrams should be available online, or a car diagnostics tool might also help.

You were spot on. It turned out to be a defective plug connection on the coolant fan control module. 95€ later, it's all sorted. Thanks for pointing me in the right direction!