P0720Powertrain
Output speed sensor — malfunction
Where to start
The output speed sensor circuit. It differs from P0717 in that the speedometer usually lies as well as the shifting. The cause is the same and in the same place: a connector underneath, dirt, a chafed wire.
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 thisTransmission codes: P0700, P0715, P0720, P0741, P0750
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 engineTransmission
Number of the faultThe serial number inside that group — it does not say how serious the fault is
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.