P0561Powertrain
System voltage unstable
Where to start
The voltage is UNSTABLE — it jumps. Worse than merely low: spikes knock units over all across the car. Check the alternator brushes and regulator, the belt tension and the terminals. Voltage shows in live data: at a warm idle it should sit near 14 volts and not dance.
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 thisCharging and voltage: P0560, P0561, P0620, P0621, P0622
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 engineIdle and auxiliary systems
Number of the faultThe serial number inside that group — it does not say how serious the fault is
All codes in «Idle and auxiliary systems»
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.