[A10U]

Hi, I recently bought a 2007 e93 325i. Drove it home roughly 50 miles, no issues and very smooth. Following day, whilst driving at around 60, an overheat warning came on and lost all power. Pulled over immediately and called RAC. They found the coolant reservoir very Low so topped it up. Pressure tested and no apparent leaks to pump. Diagnostics is showing a communication problem (pic attached).
Drove roughly half a mile and same overheating warning came up and lost power again. Managed to get home, mile and a half with help from RAC.
Contacted garage where I bought it and they’re sending a guy to look at and order/replace the electric water pump.
Has anyone had a similar issue or have an idea of what might be the problem?
Ps temperature gauge never went above 100*c and although registering as overheating, water was cold.

Many thanks