Saxo Transmission Issues

That sounds incredibly frustrating! I had a similar problem with my old Alfa Romeo a while back. The symptoms were almost identical – wouldn't start, check engine light, and weird shifting. It turned out to be a faulty transmission sensor sending incorrect data to the ECU. Is it possible your park brake switch is defective? It might not be sending the right signal, preventing the engine from starting.

Interesting, thanks for the tip! I didn't think about the park brake switch. When your Alfa had this issue, was it also throwing transmission error codes? Did you have to replace the entire control unit, or was it just the sensor?

Yes, it was throwing transmission error codes like crazy. Luckily, it wasn't the entire control unit, just the sensor. However, it took a while to diagnose properly. Given all the symptoms you're describing, and the fact that it's preventing the car from starting, I'd recommend getting it checked out by a specialist. It could save you a lot of time and potential misdiagnosis, and potentially 1000€ as I paid back then...

Thanks a lot for your help and sharing your experience! I appreciate it. I'll take it to a workshop to get a professional opinion. The control unit was indeed defective, as suggested by the error codes. Now it runs like new!