Hi
I am a useless mechanic and engineer.
Needs must however and in my younger days I had to service and repair my cars.
I managed to do that.
No chance now, you need a reader to find the fault and then reset the engine.
All I can do is do my tyres, oil, screenwash and petrol, and that’s about it. 
You can buy code readers to interpret any fault codes , but unless you know where the components are that need changing, you’re pretty much stuffed,