To start a car,  fuel, air, spark, and compression are important. And various factors such as starter motor, battery, fuel pump, fuse, relay, camshaft sensor, crankshaft sensor and others make differences in starting the car. Before any diagnosis, battery, fuse and relay should first be checked.

For less experienced drivers, there are easier ways to find out what the starting issues are as below. Of course, this is the general case and there should be unique situations as well.

1. No sound
2. Tick or tak once or twice
3. Ta ta ta ta ta continuous sound
4. Continuous clunking sound
5. Starts only in N gear

​The cases 1 and 2 are most likely due to a failure in the starting motor side, number 3 for battery discharge, and number 4 for other reasons such as fuel pressure. This diagnostic method is mostly applicable to vehicles with internal combustion engines.

​The 4th case can be tricky. However, using sensor values ​​such as STFT (Short term fuel trim), LTFT (Long term fuel trim), RPM, fuel amount, engine load, MAF (Mass air flow sensor), and throttle body, further diagnosis is suggested.

The 5th case could be neutral safety switch or transmissiin range switch or inhibitor switch issue.

The 4th and 5th cases should be done by experienced  users or by a professional technician.