Before diagnosing starter issues, ensure a fully charged battery. If the starter motor doesn't turn, check the shift lever is in Neutral or Park and the battery is charged with secure cables. If the motor spins but the engine doesn't turn over, the starter motor may need replacing. If the motor doesn't operate but the relay/solenoid clicks, the problem could be the battery, relay/solenoid contacts, or motor connections; if it doesn't click, there may be an open circuit or a defective relay/solenoid. Check the circuit and test with a jumper wire and if the motor operates, the issue could be the ignition switch, Neutral start switch, or circuit wiring. If not, replace the relay/solenoid. If the motor cranks the engine slowly, ensure a fully charged battery, clean and tight terminal connections, and check for a short to ground. Consider a partially seized engine or incorrect oil viscosity.