Vauxhall Vectra Gear Selection Display Issue

That sounds like a complex issue. Have you checked the transmission fluid level recently? Low fluid can cause slipping and shifting problems. Also, are there any other warning lights illuminated on the dashboard besides the gear selection indicator? It might be useful to read the specific error code stored in the memory; that could give a more precise indication of the problem area.

Thank you for your swift response. The transmission fluid level appears to be within the acceptable range. In addition to the gear selection display malfunction, there are no other warning lights illuminated. Could a defective control unit truly cause such a wide array of symptoms, or are there other potential causes I should investigate before considering that option?

While other factors could contribute, the symptoms you describe strongly suggest a fault within the transmission control unit. Given the implausible shifting, inability to engage gears, and the stored error code, a defective control unit is the most probable cause. I suggest visiting a qualified workshop to have the unit properly diagnosed and replaced.

I appreciate your expert advice. I took the vehicle to a trusted workshop, and after their diagnostics, they confirmed that the control unit was indeed defective. The replacement cost, including labor, amounted to 1000€. Thank you for pointing me in the right direction.