Diagnosing a car's electronics

If your car was made (roughly) after 1995, its engine most likely has an electronic fuel injection control system (a computer). What's more, in most modern cars, computers also control the automatic transmission (AT), the air conditioning system and other important components. If there's a computer, there's definitely also a memory unit that automatically logs errors in how the sensors and components are working.

Some errors can show up periodically (intermittent errors), and they're not necessarily tied to faulty parts and sensors — they can also stem from, say, using low-quality fuel, or the fuel system being incorrectly tuned. There can be many causes, but in any case the place to start is by reading out the error memory and consulting an auto electrician who has the necessary equipment and experience to diagnose your particular car. It's worth saying that official garages have all this, but the cost of a consultation there is often significantly inflated, so start by reading the relevant thread on a specialised online forum — where you'll find owners of cars of the same make and model as yours, and you might find a more affordable option that's just as good.

It should be said right away that the mere fact that a car drives normally and the engine sounds normal doesn't mean there are no errors. Many errors aren't considered critical, so car manufacturers don't see the need to put a warning light on the dashboard for them. But, at the same time, an oxygen sensor error, for example, which you'd have no other way of noticing, can double fuel consumption compared to the normal figure for your engine.

If the errors found during diagnostics are only related to adjustment, try to fix them right away; if some parts or sensors need replacing, add them to your overall list.</content>