Mondeo Automatic Transmission Problems

The symptoms you described (engine not starting, check engine light, rough shifting, error code) do suggest a problem within the transmission system. Have you observed any unusual noises coming from the transmission, or any fluid leaks underneath the vehicle?

I haven't noticed any weird noises, and no obvious leaks either. The fluid levels seemed okay when I checked them. The error code pointed towards a possible control unit malfunction. Could a defective control unit really cause all these problems at once?

Yes, a defective control unit can certainly manifest the combination of symptoms you're observing. It's plausible that a fault within the transmission control unit is preventing the engine from starting and causing the erratic shifting. Given the diagnostic findings and symptoms, it would be advisable to consult a qualified workshop for a comprehensive assessment. It is likely a control unit issue. It could be in the realm of 1000€, based on my past experience.

Thanks so much for confirming that suspicion! I was hoping it wouldn't come to that, but it sounds like a trip to the workshop is unavoidable. At least I have a better idea of what to expect now. Thanks again for the insights!