Possible reasons:
* Discharged battery: Check the battery voltage with a voltmeter. If it is below 12.6 V, the battery needs to be charged or replaced.
*Faulty Starter: The starter may be faulty, causing no power to be supplied to the engine.
* Broken Wires: Check the wires for breaks or damage, especially near the battery and starter.
* Failed alternator: The alternator cannot charge the battery, which eventually leads to battery drain.
* Ignition switch problems: The ignition switch does not send a signal to the starter to start the engine.
*Faulty crankshaft or camshaft sensor: These sensors provide a timing signal to the electronic engine control unit (ECU), which is required to start the engine.
* Failed ECU: The ECU cannot control the engine starting system and other necessary functions.
Diagnosis and solution to the problem:
* Check the battery: Use a voltmeter to check the battery voltage. If it is low, charge or replace the battery.
* Check the starter: Try turning on the headlights for a few seconds. If the headlights are dim or do not light up, this may indicate a faulty starter.
* Check Wires: Inspect the wires for breaks or damage. Replace any damaged wires.
* Check the alternator: If the engine still does not start after charging the battery, check the alternator for problems.
* Check the ignition switch: Try turning the ignition key to the “Start” position. If the engine does not start, check the ignition switch for problems.
* Check crankshaft and camshaft sensors: Use a diagnostic scan tool to check for trouble codes associated with these sensors.
* Check the ECU: If other diagnostic steps fail, have the ECU diagnosed and replaced by a qualified mechanic.
Note: If you are unsure of your technical skills, it is recommended that you contact a qualified mechanic for diagnosis and repair.