Although there are many obd2 tools in the market for auto repair, some are not need to fix with them. In some cases, you can fix your car by knowing what factors may cause the issues. Here I take factors causing your car fail to start for example.

Fuse is the first factor you can check. And then you should have your battery check, for over time your battery connections can become dirty, or corroded. If it wont start, it may be because the battery is dead. You can use a car diagnostic tool or battery tester to have it tested. If it is a dead battery, replace the battery and clean the battery connections to ensure good contact.

Thirdly, it maybe caused by bad ignition switch. If your battery checks out, but the starter is still silent, it may be a faulty ignition switch. Fourth is bad starter connection, corrosion can not only keep your battery from connecting, it can affect any electrical component, especially the ones exposed to the elements like the starter. Therefore, you should pay attention to these factors if your car fails to start.

However, if you check one by one maybe spend you much time and energy in it. You should find a proper diagnostic tool to have it checked for your car, just as using sds for Suzuki to check why engine at halt, AK300 for making keys and so on. to do thing by using proper method is excellent.