14 Reasons Why Your Car Won't Start

Imagine this: you're rushing out the door, you're already running late, and you hop into your car, only to be greeted with silence. You try to start it again, but nothing happens. The engine just won't start. Frustration builds as you wonder why your car won't start.

We've all been there, and it's never a good feeling. Whether it's a dead battery, a faulty starter or something as simple as being out of fuel , there are several reasons why your car might be refusing to start. In this post, we'll dive into the most common causes behind this issue and give you actionable tips to get back on the road.

1. The Battery Is Dead or Dying

The most common reason your car won't start is a bad alternator or battery, so it's the first thing you should check.

How to Tell If It's the Battery:

• Dim dashboard lights
• Radio issues: The radio cuts in and out.
• Corroded battery terminal
• Battery age: It's been over 3-5 years since you last replaced it.
• Swollen battery: A swollen battery is a serious issue , do not attempt to jump-start it, as it may burst and release battery acid. Call roadside assistance immediately.
• Rotten egg smell: You notice a sulfuric odor from the engine area.
• Clicking sound or silence: When you turn the key, you either hear a clicking noise or nothing at all.

What to Do:

• Try jump-starting your car: If it starts, drive directly to an auto repair shop or parts store for a replacement.
• Call roadside assistance: If jump-starting doesn't work, you'll need a tow to a repair facility. If you are a AAA member, our roadside assistance team will try jumping your vehicle for you. If it still doesn't start, we'll replace it on the spot or tow you to the nearest auto repair shop.

2. The Alternator Has Gone Bad

The alternator supplies electricity to various car components, such as the lights and stereo system and recharges the battery while the engine is running. If the alternator fails, it can drain the battery and cause electrical issues throughout your vehicle.

How to Tell If It's the Alternator:

• Dim or flickering lights: Your headlights appear more cloudy than usual.
• Weak audio system: The stereo output sounds weaker or cuts out intermittently.
• Dashboard warning light: You may see a battery-shaped warning light on your dashboard.
• Burning rubber or electrical smell: A strange odor could indicate alternator problems.
• Battery constantly dying: Even after replacing the battery, it drains quickly.
• Grinding or whining noise: You hear unusual sounds from under the hood when the engine is running.

What to Do:

• Test your alternator: Use a multimeter set to DC voltage. With the car off, a healthy battery should read around 12.6 volts. Start the car, and the reading should jump between 13.8 and 14.2 volts. Your alternator likely needs attention if the voltage drops below 13 volts when you turn on electrical accessories (like headlights or AC) or spikes above 15 volts. We highly recommend going to a professional to get this handled.
• Visit an auto repair shop: If you're unsure about the alternator's condition or don't feel confident testing it yourself , have a professional run a diagnostic test. A healthy alternator should produce around 13.8 to 14.2 volts.
• Call roadside assistance: If your car won't start and you suspect alternator issues, you may need a tow to a repair shop.

3. The Starter Is Faulty

The starter is a critical component that helps spin the engine to build compression, getting your car up and running. If it fails, the car won't start , hence the name. Thankfully, there are usually some warning signs before a complete failure.

How to Tell If It's the Starter:

• Low engine crank: The engine cranks slowly when you try to start the car.
• Electrical issues: If the dashboard lights turn on when you attempt to start the car but nothing else happens, it could be the starter.
• Lights but no start: If you hear a single click or nothing at all while the dashboard lights still come on, the starter is likely the issue.

What to Do:

• Visit a repair shop: A faulty starter can't be easily fixed on your own because it often requires specialized tools and expertise to access and replace the part. You'll need to take your car to your nearest dealership or auto repair shop for a proper diagnosis and replacement.

4. The Ignition Switch Is Jammed or Broken

If your battery is in good shape but your car still won't start, the issue might be with the ignition switch , a component that controls the power flow to your vehicle's electrical system and starts the engine when you turn the key or press the start button.

How to Tell If It's the Ignition Switch:

• Flickering dashboard lights: Your dashboard lights might flicker or not turn on at all when you attempt to start the car.
• Key won't turn: The key is stuck in the ignition or won't turn smoothly.
• No engine noise: You don't hear any engine cranking, only silence.
• Accessories won't power on: If the radio, lights and other accessories don't turn on when the key is in the "On" position.
• Intermittent starting issues: Your car starts sometimes but not always, which can indicate a failing ignition switch.

What to Do:

• Wiggle the steering wheel: If the key won't turn, try gently wiggling the steering wheel as you turn the key; sometimes, the steering lock mechanism can cause the ignition to jam.
• Use a spare key: Your key might be worn out. If you have a backup key, try using it.
• Call a professional: If these tips don't work, you may need a tow to a repair shop for ignition switch replacement or repair.

5. The Spark Plugs Are Old or Dirty

Spark plugs ignite the air-fuel mixture in your engine. Over time, they can become worn out or dirty, preventing your car from starting properly.

How to Tell If It's the Spark Plugs:

• Engine misfires: You may notice the engine sputtering or stalling when you try to start it.
• Poor acceleration: The car may feel sluggish when you press the gas pedal.
• Rough idling: Your engine may idle roughly or shake when the car is in gear.
• Check engine light: If the spark plugs are faulty, the check engine light may turn on.
• Fuel smell: A strong smell of fuel may indicate incomplete combustion caused by bad spark plugs.

What to Do:

• Replace spark plugs: If the plugs are too worn or damaged, it's best to replace them. AAA repair facilities are equipped to diagnose and replace a bad spark plug.
• Call roadside assistance: If you can't start your car or replace the spark plugs, you'll need a tow to the nearest auto repair shop.

6. There's a Problem With the Ground Cable

If your car won't start, it could be an issue with the ground cable, which connects the car's battery to the engine and chassis. A faulty or loose ground cable can prevent electrical current from flowing properly, causing starting issues.

How to Tell If It's the Ground Cable:

• Loose connection: The cable may be visibly loose or disconnected from the battery or engine.
• Corrosion: Corrosion around the ground cable connection can interfere with the electrical flow.
• Flickering lights: If your dashboard or headlights flicker, it could indicate a grounding issue.
• Engine struggles to turn over: When you turn the key, the engine may struggle or fail to crank.

What to Do:

• Inspect the ground cable: Look for any loose connections or visible corrosion. If you find any, you may be able to tighten the connection.
• Clean corrosion: If the ground cable is corroded, clean it with a wire brush or baking soda and water solution.
• Replace the cable: If cleaning doesn't help or the cable appears damaged, replace it. If you can't fix it yourself, call roadside assistance for help or a tow to an auto repair shop.

7. Your Car Has a Blown Fuse

Another common reason your car might not start is a blown fuse. Fuses are designed to protect your car's electrical system, and if one blows, it could prevent vital components, like the ignition system, from functioning.

How to Tell If It's a Blown Fuse:

• Car accessories don't work: If your lights, radio or air conditioning suddenly stop working.
• No power to the ignition: The engine doesn't turn over when you try to start the car, but other electrical components seem fine.
• Burnt smell or discoloration: You might notice a burnt smell near the fuse box or discoloration around the fuse.

What to Do:

• Check the fuse box: Locate your car's fuse box (usually under the dashboard or in the engine compartment). Look for any blown fuses; these have a broken wire inside or appear blackened.
• Replace the blown fuse: If you find a blown fuse, have a qualified technician diagnose the electrical system for that component/fuse to determine the root cause of failure.
• Call a mechanic if needed: If replacing the fuse doesn't solve the issue, call a mechanic or roadside assistance for help.

8. Your Car Doesn't Have Enough Gas

It might sound obvious, but running out of gas is an easy mistake to make, especially if your fuel gauge is faulty or you've been driving on "E" for too long.

How to Tell If It's a Gas Issue:

• Fuel gauge reads empty: The most straightforward sign is that your fuel gauge is at or near empty.
• Sputtering engine: The engine may sputter or stall right before it shuts down completely.
• Car cranks but won't start: If the engine turns over but doesn't start, low fuel could be the cause.

What to Do:

• Refuel the car: If you're near a gas station, add a few gallons to see if that resolves the issue.
• Use a gas can: If you're stranded far from a station, you might need to use a gas can to bring fuel to your car.
• Call roadside assistance: If you can't get gas yourself, consider calling roadside assistance for fuel delivery.

9. The Fuel Filter Is Clogged

A clogged fuel filter can prevent fuel from reaching your engine, leaving your car unable to start. Over time, dirt and debris can accumulate in the filter, restricting the flow of fuel.

How to Tell If It's a Clogged Fuel Filter:

• Engine sputters: The engine may sputter or stall shortly after starting.
• Difficulty accelerating: Your car struggles to accelerate or feels sluggish when you press the gas pedal.
• Frequent stalling: The car frequently stalls, especially when driving uphill or under heavy loads.
• No start but cranks: The engine cranks but doesn't start, indicating that fuel isn't reaching the engine properly.
• Fuel efficiency drop: A noticeable decrease in gas mileage.

What to Do:

• Replace the fuel filter: If the filter is clogged, it's best to replace it. Check your manufacturer's recommended maintenance schedule to determine how often the fuel filter should be replaced.
• Seek professional help: If you're unsure or if replacing the fuel filter doesn't solve the issue, have your car towed to a repair shop for a thorough diagnosis.

10. The Fuel Pump Relay Failed

A failed fuel pump relay could be the culprit if your car won't start. This small but crucial component controls the power to your fuel pump, meaning your engine won't receive the fuel it needs to start.

How to Tell If It's the Fuel Pump Relay:

• Engine cranks but doesn't start: The engine turns over but doesn't fully start.
• No sound from the fuel pump: When you turn the key to the €œOn€ position, you usually hear a faint hum from the fuel pump. If it's silent, the relay could be faulty.
• Intermittent stalling: Your car starts but then suddenly stalls, especially when idling or accelerating.
• Check engine light: A warning light on your dashboard may indicate a fuel system issue.

What to Do:

• Inspect the relay: Locate your car's fuse box and find the fuel pump relay. Swap it with another relay of the same type to see if that resolves the issue.
• Try a restart: If the car starts after swapping the relays, you must replace the faulty fuel pump relay.
• Call for professional help: If troubleshooting doesn't work, it's best to call a mechanic or roadside assistance to avoid further damage to your car's fuel system.

11. The Timing Belt Is Worn Out

The timing belt is a rubber belt with teeth that ensures the engine's valves open and close at the right intervals, coordinating with the pistons' movements. A worn-out timing belt can prevent your car from starting by disrupting the synchronization between the engine's camshaft and crankshaft. If the belt snaps or slips, the engine may fail to turn over, leaving you stranded.

How to Tell If It's the Timing Belt:

• Noisy engine: You may hear a ticking or rattling noise from the engine when trying to start the car.
• Engine won't turn over: If the timing belt breaks while driving, the engine will stop abruptly and won't restart.
• Check engine light: A malfunctioning timing belt, especially if the engine misfires, may trigger the check engine light.
• Visible wear and tear: If you can inspect the timing belt, look for signs of cracks, fraying or glazing.

What to Do:

• Stop trying to start the car: If you suspect a timing belt issue, avoid turning the key repeatedly, which can cause severe engine damage.
• Check your maintenance schedule: Timing belts typically need replacement every 60,000 to 100,000 miles. If you're overdue for this service, it's likely the cause.
• Call a mechanic immediately: A worn-out or broken timing belt requires professional repair. Arrange for a tow to a repair shop to prevent further damage to the engine.

12. The Steering Lock Is Engaged

If your car won't start, it could be because the steering lock is engaged. The steering lock is an anti-theft feature that prevents the steering wheel from turning unless the correct key is used, which can also block the ignition from starting.

How to Tell If the Steering Lock Is Engaged:

• Steering wheel won't turn: The steering wheel feels stuck and won't budge when you try to move it.
• Key won't turn on the ignition: Even if you insert the key correctly, it may be difficult or impossible to turn it.
• Warning lights on the dashboard: You might see a steering wheel or key symbol light up, indicating an issue with the steering lock system.

What to Do:

• Gently jiggle the steering wheel: While turning the key in the ignition, gently move the steering wheel side to side. This can disengage the steering lock.
• Avoid forcing the key: Don't apply excessive force, which can break the key or damage the ignition switch.
• Try another key: If you have a spare, use it to see if the issue is related to a worn-out key.
• Call for assistance: If the steering lock remains engaged, contact a mechanic or roadside assistance for further help.

13. The Key Fob Battery Is Dead or Dying

If your car won't start and uses a push-button ignition, the issue might be a dead or dying key fob battery. The key fob sends a signal to your car to unlock the doors and start the engine, but if its battery is depleted, the car may not recognize it.

How to Tell If It's the Key Fob Battery:

• No response when pressing the start button: You press the ignition button, but nothing happens, or you see a "key not detected" message on the dashboard.
• Door locks aren't working: The key fob won't lock or unlock the doors, even at close range.
• Dim or no lights on the key fob: If your key fob has a light indicator, it may be dim or completely unresponsive.
• You have to hold the key fob closer: If you need to press buttons multiple times or hold the fob close to the start button to get a response.

What to Do:

• Use the manual key: Many key fobs have a hidden physical key inside. Use it to unlock the car door and try starting the car by holding the key fob near the start button (check your owner's manual for the exact location).
• Replace the key fob battery: If you have a spare key fob battery, swap it out.
• Start the car with the key fob: Some vehicles have a backup way to start the car using a dead key fob, such as placing it in a designated spot on the dashboard.
• Contact roadside assistance: If you can't start your car, call for roadside assistance or a locksmith who can provide a replacement key fob battery.

14. The Car Isn't in Park or Neutral (Or the Neutral Safety Switch Is Faulty)

If your car won't start, it could be because it isn't properly set in the €œPark€ or €œNeutral€ gear. Automatic cars have a neutral safety switch that prevents the engine from starting unless the transmission is in either of these positions. A malfunctioning neutral safety switch can also cause starting issues.

How to Tell

• The engine doesn't crank: You turn the key or press the start button, but nothing happens and there are no clicking sounds.
• Dashboard gear indicator is off: The gear indicator on your dashboard may not align with the gear you've selected, indicating it's not fully in €œPark€ or €œNeutral.€
• Shifting into neutral works: If the car doesn't start in €œPark€ but starts in €œNeutral,€ it could be a sign of a faulty neutral safety switch.
• Car starts intermittently: The car sometimes starts without issue but fails other times, especially when shifting gears.

What to Do:

• Ensure the car is fully in €œPark€: Firmly move the shifter into the €œPark€ position and try starting the car again.
• Try starting in €œNeutral€: If it doesn't start in €œPark,€ shift to €œNeutral€ and attempt to start the engine.
• Jiggle the gear shifter: Sometimes, the gear lever may not be fully engaged. Slightly moving it while trying to start the car can help.
• Call a mechanic: If none of the above works, you may have a faulty neutral safety switch that needs professional inspection and replacement.

What To Do if Your Car Won't Start

Take a few minutes to become a AAA member today! If your car doesn't start, our roadside assistance team may be able to solve the problem on-site (if you need a jump or a car battery replacement, for example) or tow you to the nearest auto repair shop.

All AAA-approved auto repair facilities employ Automotive Service Excellent (ASE) certified or factory-trained technicians, so you can trust you'll get the right repair and get back on the road. Plus, you'll save at least 10 percent on labor costs with your AAA membership.

FAQs

What if my car has power but won't start?

If your car has power , meaning the lights, radio and dashboard indicators turn on , but it still won't start, the issue may be with the starter motor, ignition switch or fuel system. You might hear a clicking sound, which usually indicates a bad starter. Another possibility is a failed fuel pump or relay preventing fuel from reaching the engine. It's best to check these components or consult a mechanic.

What if my car won't start, but the battery is fine?

If the battery is in good condition, but your car still won't start, the problem might lie in other critical components like the alternator, spark plugs or fuel delivery system. It could also be due to a malfunctioning neutral safety switch or a blown fuse. Issues like a faulty crankshaft position sensor or a damaged timing belt can prevent the engine from starting despite having a charged battery.