Step 1: Check the Battery
 

• Locate the battery under the hood of your Elantra and visually inspect it for any obvious signs of damage such as corrosion on the terminals or leakage.
• Use a multimeter to measure the battery voltage. A fully charged battery should read around 12.6 volts or slightly higher. If the voltage is significantly lower, the battery might need to be recharged or replaced.
• Ensure the battery cables and terminals are securely connected, and clean any corrosion using a wire brush and a mixture of baking soda and water.

 
Step 2: Inspect the Starter Motor
 

• Check for any clicking noises when attempting to start the vehicle; this can be a sign of a faulty starter motor.
• Locate the starter motor (typically near the transmission) and visually inspect it for any loose connections or damaged wires.
• If the starter motor looks physically intact, it might need a professional inspection to test its condition or for possible replacement.

 
Step 3: Examine the Alternator
 

• A malfunctioning alternator can lead to an undercharged battery. Check the alternator belt for any signs of wear or looseness.
• Use a multimeter to measure the output voltage of the alternator with the engine running. It should be between 13.5 and 14.5 volts. If it's lower, the alternator may need to be repaired or replaced.

 
Step 4: Test the Ignition System
 

• Inspect the ignition switch operation. Faulty ignition switches can prevent the starter motor from receiving power.
• Test that the key fob is functioning properly. Sometimes, a weak battery in the key fob can lead to starting problems.
• Check for any warning lights relating to the immobilizer system on the dashboard that might indicate an issue with the car's security system.

 
Step 5: Diagnose the Fuel System
 

• Though mainly electrical, starting issues can sometimes relate to fuel system problems. Ensure that the fuel pump is operational and delivering fuel correctly.
• Check the fuel relay and fuses for continuity, as a blown fuse can disrupt the power flow to the fuel pump.

 
Step 6: Inspect Electrical Wiring
 

• Look for any broken or frayed wires that could be causing a short in the system. Pay particular attention to cables near the battery, alternator, and starter motor.
• Test the continuity of suspect wires using a multimeter. Replace or repair any damaged wiring.

 
Step 7: Check the Onboard Diagnostics (OBD-II) System
 

• Use an OBD-II scanner to check for any diagnostic trouble codes (DTCs) that could provide clues to the underlying electrical problem.
• Address any codes by consulting the car’s service manual or a professional mechanic to interpret and resolve them.

 
Step 8: Professional Assistance
 

• If all else fails, or if you are not comfortable performing these checks, seek help from a certified mechanic who specializes in Hyundai vehicles.
• They can provide a more thorough inspection using specialized diagnostic tools, ensuring the root cause of the problem is correctly identified and resolved.