P0381Powertrain
Glow plug indicator lamp — circuit malfunction
Where to start
The glow plug lamp circuit. The lamp on the dashboard is not the point — the code is about its circuit or the glow control module. The car may start hard when cold, so it is better not to leave this until the frost.
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 thisA diesel in winter: glow plugs, the DPF and the fuel
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 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.