Q: Rapid clicking when trying to start engine

Hi there. It sounds like you have either a faulty battery or a failed starter. If the battery has failed, insufficient voltage and amps are supplied to the starter and it cannot turn the engine. If the starter motor has failed, then the motor can no longer support the load of turning the engine. What you’re most likely hearing is the solenoid arm that moves outward to engage the flywheel and turn the engine for starting. I would start with a battery test via a digital tester that provides current voltage, cold cranking amps, and state of health. After this, proceed with checking for proper voltage at the starter. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several technicians available that can assist you with a no start inspection.