P0037Powertrain
O2 sensor heater circuit low (bank 1, sensor 2)
Where to start
The rear oxygen sensor heater circuit. Check the same things — fuse, connector, wire. The sensor itself is replaced last.
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, general
Number of the faultThe serial number inside that group — it does not say how serious the fault is
All codes in «Fuel and air metering, general»
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.