P0133Powertrain
Upstream O2 sensor slow response (bank 1) — usually a worn sensor
Where to start
The oxygen sensor responds sluggishly — usually just age, as they last around 100,000 km. Before replacing it, make sure there is no air leak and that the engine warms up fully: an under-heated engine produces a similar picture.
A code is not a diagnosis. It says which check failed, not which part to replace. Clearing it without repair only means the car will report it again in a few trips.
How to put together a report a mechanic will actually read
We have a detailed piece on thisThe oxygen sensor: telling from live data that it is tired
How the code is built
Letter — the systemPowertrain: engine and transmission
Common or the maker's ownGeneric code: the same on every car
Which part of the engineFuel and air metering
Number of the faultThe serial number inside that group — it does not say how serious the fault is
How it feels behind the wheel
The same fault shows itself in different ways. Each sign below says what to look at in the live data.
How the app helps
CarScan reads this code from your car through an OBD-II adapter, shows whether it is active now or only stored, names the module that reported it, and puts it into a plain-text report for your mechanic.