P0100Powertrain
Mass air flow circuit malfunction
Where to start
The mass air flow sensor circuit. The word «circuit» matters more than the word «sensor» here: a connector or a chafed wire is to blame more often than the part itself. Wiggle the connector with the engine running and watch whether the reading jumps.
What to watch in live data
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 MAF sensor: signs of wear and a live-data check
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
All codes in «Intake measuring sensors»
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.