Nemo Gear Shift Indicator Problem

The symptoms you describe, specifically the inability to engage gears coupled with a non-functional gear selection display, strongly suggest an issue within the transmission control system. While a generic OBD reader may retrieve a code, it might not provide sufficient detail for accurate diagnosis. Could you possibly provide the specific error code you retrieved? Also, has the vehicle experienced any recent maintenance or repairs related to the transmission?

Thanks for the quick reply! The error code is P1755, but I'm not sure what it means in this case. The car hasn't had any transmission work recently, just regular servicing like oil changes. Is it possible that a faulty sensor is causing this?

Error code P1755 typically indicates a problem within the transmission control module itself. Given the error code, alongside the other symptoms, the affected control unit could very well be defective. In these circumstances, I would highly recommend taking the vehicle to a qualified workshop with Citroen-specific diagnostic equipment. The cost of repair may be in the region of 1000€

Okay, I understand. Thanks a lot for your help! I'll take it to a workshop to get it checked out properly. You were spot on - it turned out to be a defective control unit. I got it replaced and it cost me around 1000€. Everything is working fine now. Thanks again!