Modern car's today rely heavily on onboard computer systems. These computer systems are called ECUs: electric control units. These computer systems help manage all the auto electric repairs in your car. Understanding your car's electrical systems therefore has to start with understanding your car's ECU and what it does.
How it's set up
Your car's ECU is found under the hood and makes up the 'brain' of your car's electrical system. It monitors your engine's fuel intake, your transmission speeds and shifting, your exhaust system oxygen sensors, car lighting, sound, alarm systems, central locking, battery charge, windscreen wipers, air conditioning and other electrical systems in your car. The newer your car is the more electrical systems you have controlled by the ECU.
Benefits of the ECU
Since your car's on board computer is accurate, it can better monitor your cars 'vitals'. This is why modern cars can attain better fuel economy as the ECU has sensors that gauge your gas pedal and speeds to better control fuel intake. In the same way, the ECU maximizes performance by ensuring better shifting efficiency as per the engine's RPM. When something goes wrong in your car, you car's ECU can detect it way before you start to see the symptoms of a bad engine or transmission. Your ECU can detect even the slightest damage such as blown fuses. Your car's onboard computer therefore makes your car safer and more efficient on the road.
Maintenance & repairs
When you have a problem in any of your car's electrical system, your ECU will give you a notification on your dashboard. A check engine light, for example, can be due to low engine oil or a leak, it could also relate to the transmission system or transmission fluid. Thanks to an electrical control unit, much of the guesswork is eliminated. All your mechanic has to do is connect your ECU to an electrical diagnostics computer and they can check any reported errors by the ECU. The errors will enable your mechanic to immediately identify the problem areas and correct them. The ECU may report that your battery should be replaced soon, that you need to change the transmission fluid or simple problems like a faulty solenoid. Your mechanic will then fix those problems and refresh your ECU.
In some rare cases, your ECU may still persist that you have certain errors even after they have been fixed. This can be due to faulty sensors or solenoids that will then need to be replaced. Once done, your ECU will be 'flushed' to rid the bad memory and restarted afresh.