P0300Powertrain
Random/multiple cylinder misfire detected
Where to start
Misfire in several cylinders at once. Spark plugs, coils, air in the fuel. Do not drive long with this code: unburnt fuel kills the catalytic converter.
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 thisMisfires: P0300, P0301 and why you should not keep driving
Step by stepHow to find which cylinder is misfiring
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 engineIgnition system and misfires
Number of the faultThe serial number inside that group — it does not say how serious the fault is
All codes in «Ignition system and misfires»
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.
The engine stumblesThe engine runs unevenly, the car shakes at idle, the exhaust note stutters. On the move the pull sags and consumption rises.It jerks under accelerationAt steady throttle everything is fine, but under acceleration the car jerks or hesitates, as if the pedal was released for a moment.Smoke from the exhaustVisible smoke from the tailpipe. The colour is the clue: white, blue and black mean entirely different things.Check engine came on after a wash or heavy rainYou washed the car or drove through a downpour — and the light came on. It often clears itself in a day or two.
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.