Lexus LX Transmission Issues

Sounds like your LX is having a rough time. Low transmission oil definitely can cause those symptoms. The sensor relies on being submerged in the oil to get an accurate reading. If the level's low, it might be giving false readings, triggering the warning lights and putting the gearbox into limp mode. Grinding noise is also consistent with low oil, as the gears aren't getting properly lubricated. How many kilometers are on it?

Okay, that makes sense regarding the oil level affecting the sensor. The mileage is currently at 140307 km. Is it possible that the sensor is malfunctioning because it's old rather than because of the oil level, or are the symptoms too related to low oil? How would you verify the sensor is working correctly?

Mileage is relevant, but the symptoms you described are highly suggestive of low oil – the grinding noise especially. A failing sensor could cause issues, but it’s less likely to cause the physical symptoms you're experiencing. To properly test the sensor, you'd need a multimeter and the factory service manual for the LX to check the resistance values at different temperatures. Honestly, at this point, I'd suggest taking it to a reputable workshop, because your LX transmission issues should be addressed by a professional.

Thanks a ton for the advice! I decided to take it to my local mechanic, and you were spot on. Turns out, the gearbox oil level was indeed low. They topped it up after a system check, replaced the faulty sensor, and cleared the error codes, and it's running like a champ again. Total damage was 365€, but worth it to avoid a complete transmission failure. Appreciate the help!