Cars and trucks are not just mechanical parts working separately. In modern cars and trucks, all the parts are working in unison and they are being controlled by the Electronic Control Unit or ECU.
The ECU consists of separate modules such as Powertrain Control Module, Engine Control Module, Transmission Control Module, Brake Control Module, Central Timing Module, Suspension Control Module, General Electronic Module, Central Control Module, Body Control Module, and control module. You can check this link https://npcautomotive.com/ to know about automotive computers.
Each of these modules is responsible for controlling their specific subsystems through actuators and sensors. The sensors in different subsystems send readings about various parameters resulting from the functioning of that subsystem.
The actuators, on the other hand, are ones that control various functions of different subsystems. So there are actuators to control fuel injectors, oxygen mixing, etc. It is an integrated system working to run the car under perfect conditions to minimize emissions and fuel consumption and maximize ride comfort and powertrain.
What happens is there is a problem with any of the subsystems? The ECU shows the check engine light. But this light may indicate a wide range of problems. You need an Automotive Scan Tool to decipher the real problem.
Automotive Scan Tool
An automotive scan tool is designed to talk to the ECU or the modules in it and bring out precise information. Information is stored in the ECU, but in codes. These are the trouble codes and there is a vast range of them. You need to have a device which can interpret these codes and bring out the specific problem with the car.
This is where an Automotive Scan Tool is very useful. Such a tool can bring out all the information displayed by the OBDII and interpret them. There are great tools which can describe problems in detail and also suggest ways to work them out. There are some more efficient ones which have bidirectional capability.