Laguna Automatic Gearbox Problem

That sounds like an issue I had with my 2018 Volvo V60. Emergency mode and the TCM error code are telling. My problem was a faulty sensor within the TCM, causing communication issues with the gearbox. A defective control unit is a strong possibility. Have you checked the wiring harness and connectors leading to the TCM for damage or corrosion? Sometimes a simple electrical issue can mimic a more severe problem.

I visually inspected the wiring and connectors but didn't see anything obvious. When you had that Volvo problem, did the error code specifically point to the TCM, or was it more vague? Did you try anything else before replacing the TCM?

I recall the error code being specific to the TCM, but I don't remember the exact code. Before replacing it, dealer technicians performed a thorough diagnostic check, including testing the TCM's inputs and outputs. DIY repairs can be risky without the right tools and expertise. I suggest a qualified mechanic perform a comprehensive diagnosis. Replacement may be necessary.

I took it to a local mechanic, and they confirmed the transmission control unit was defective after a complete diagnosis. They replaced it, and now the car is shifting smoothly again. The total cost was about 1000€. Thanks for pointing me in the right direction!