P0118Powertrain
Engine coolant temperature circuit high input
Where to start
The coolant temperature sensor reports implausibly cold — usually an open circuit. The engine then pours in extra fuel, starts badly when hot and drinks noticeably more. Check the sensor connector and the wire back to the control unit.
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
Step by stepHow to tell whether the thermostat is to blame
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 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 temperature gauge is climbingThe needle goes above its usual place, there is a hot smell from under the bonnet, and the heater may blow cold on a hot engine.Slow to warm up, the heater blows coldThe temperature needle sits low for ages, the cabin stays cold, and on the motorway it gets worse. Consumption rises noticeably.The cooling fan runs all the timeThe fan roars right after starting and does not stop even on a cold engine or in frost.
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.