RC Transmission Oil Temperature Sensor Fault

Oh dear, that sounds like a very serious problem indeed! The symptoms you describe are certainly concerning, especially the emergency mode and grinding noises. Slipping gears are never a good sign! Have you checked the gearbox oil level? If the oil level is too low, it might cause the temperature sensor to give a faulty reading and lead to overheating problems as well as the other issues you are experiencing. I am not super familiar with the RC, but is checking the level something you could do yourself?

Thanks for the reply! I haven't checked the gearbox oil level myself yet, I'm not too experienced with car maintenance and don't have the tools for that. Do you know if it's a difficult procedure on the RC? I'm just wondering if it's something I could tackle at home, or if it's best left to a professional.

Given the complexity of modern transmissions and the potential for further damage if not done correctly, I would strongly advise against attempting to check or adjust the gearbox oil level yourself. The Lexus RC, being a modern hybrid, has a very sophisticated transmission system. Given the severity of the symptoms you are experiencing – the warning lights, emergency mode, slippage, and grinding noises – I believe that the best course of action would be to take your vehicle to a qualified workshop as soon as possible. They will be able to accurately diagnose the problem, determine the exact cause (whether it is indeed related to low oil level or a faulty sensor), and perform the necessary repairs. Continuing to drive the vehicle in its current condition could potentially lead to more extensive and costly damage.

Thank you so much for your advice! I took it to a workshop, and you were right. They checked the gearbox oil level and found it was indeed too low. They replaced the transmission oil temperature sensor and topped up the oil. The total repair cost was 365€. Now the shifting is smooth again, and all the warning lights are gone!