Diagnostics and troubleshooting - Toyota Ardeo, 2.0L, 2000

Drove in for diagnostics at the service station. High levels of CO and CH were confirmed. As a result of diagnostics, it turned out that the oxygen sensor was covered. In this case, the "check" did not burn. The most interesting thing is that the light bulb is in good working order, and when starting self-diagnosis, it gave an error code corresponding to the faulty oxygen generator. But in normal mode, it does not burn. They could not find out the reason. The oxygen tank was replaced, all errors were thrown off, they sent me to run the machine. Tomorrow morning I will go for a second gas analysis at this service station.