LandCruiser Oil Temperature Warning Light

Sounds like you're on the right track checking the wiring. The oil temperature sensor circuit is pretty straightforward. The ECU sends a reference voltage (usually 5V) to the sensor, and the sensor's resistance changes with temperature, which the ECU interprets. Have you checked the continuity of the wire from the sensor plug back to the ECU? Also, inspect the plug itself for corrosion or damaged pins. A high-resistance connection can definitely cause those symptoms. Do you know the exact error code that was stored?

I checked the pins and they looked fine, no corrosion visible. I haven't checked the wire continuity back to the ECU yet. I will try that. As for the code, it was something like 'P0196 Engine Oil Temperature Sensor Range/Performance'. Does that give you any other clues?

P0196 confirms the sensor circuit issue. Given that code and your symptoms, combined with the oil pressure light flickering, it's almost certainly a wiring or connection fault, like you suspected. While you can chase it down with a multimeter, honestly, at this point, especially with the oil pressure light involved (which could indicate a genuinely dangerous low-pressure situation if the sensor is actually working correctly), I'd suggest a trusted workshop. They can pinpoint the fault quickly and ensure the oil pressure system is functioning correctly. Peace of mind is worth something here.

I traced the wiring back and found a slightly corroded section near the firewall. Cleaned it up, reconnected everything, and the light's gone! The workshop confirmed the repair at 95€. Cheers!