Lexus ES Hybrid Fuel Level Sensor Issue

A faulty fuel level sensor can definitely cause those symptoms. Does the error memory indicate an implausible signal from the sensor? Have you checked the wiring and connections to the sensor for any obvious damage or corrosion? A defective fuse is the best case - I would start there.

Thanks! By error memory, do you mean the diagnostic codes it threw? And where exactly would I find the fuel level sensor fuse? I am pretty sure there is one. Is it in the fusebox under the hood, or somewhere else?

Yes, the diagnostic trouble codes (DTCs) stored in the engine control unit (ECU) are what I mean by error memory. If the error code specifically points to the fuel level sensor signal being out of range, that is important. The fuse location is usually documented in your owner's manual, or a diagram on the fuse box cover itself. If you're not comfortable checking it yourself, a workshop visit would be advisable.

Thanks a bunch for the help! I checked the fuse diagrams like you said and found the fuel level sensor fuse. It was indeed blown. Replaced it, and so far, so good. Check engine light is gone, and it idles fine. Cost me 52€ for the fuse and the diagnostic at my repair shop. Hopefully, that's the end of it!