Oxygen Sensor Heater Failure

Oxygen sensor issues, huh? I've had similar air-fuel ratio problems with my IS. Is the malfunction indicator always on, or does it come and go? Which sensor is throwing the error code? Knowing that info might help narrow down the cause. Though, a defective cable connection is plausible.

The check engine light stays on constantly. As for the sensor... I'm not sure which one. Is it possible to check that myself without special car components? Or do I need to check the exhaust system?

Given that the malfunction indicator is persistent and you're unsure which sensor is at fault, I'd advise against tampering with vehicle emissions components without proper diagnostic tools. A workshop will pinpoint the exact sensor and confirm if it's indeed a faulty connection before you start replacing car components. Trust me, it's worth preventing more damage, especially to such a clean Lexus.

Thanks for the advice. I took it to the workshop, and it was indeed a defective connection on the oxygen sensor. 95€ later, and it's fixed!