Car Dies While Driving

Car Dies While Driving – Common Causes and How to Diagnose

If your car dies while driving it’s best not to panic. Panicking will only make you unable to think clearly and make the situation worse. Most of us have been in this situation whether we like it or not. If you’ve been in this situation recently and you’re trying to find out what happened, we’ll be discussing the common reasons why your car dies while driving and how to diagnose it. But before that, here are things you should do if you find yourself in this situation:

What to Do If Your Car Dies While Driving

There are 4 steps that you should do if you notice your engine has died while you’re driving:

  1. Guide the car to the side of the road. If your car was moving when its engine died, it will probably still have enough speed and momentum for you to coast to the side of the road. If your car died while you were at a complete halt, you should push it or ask for help to push it to the side of the road. Park out of the way of other drivers to make sure you – and everyone around you – is safe.
  2. Turn on emergency blinkers. This way, drivers around you will be aware that you’ve broken down and can give you some space. Who knows, maybe a good samaritan will notice you’re in an emergency and stop by and lend you a hand.
  3. Try to start the car, if it does, then that’s great. You can drive immediately to the nearest repair shop to see what went wrong. We would advise you to drive in the right lane, so you can easily get to the shoulder should your car breakdown again.
  4. Call for help. If your car won’t start again and you’re not sure what to do, it’s time to call for help. You can either call a friend or a family that can help, or call for a towing service to at least get you off the road first. Diagnosing and fixing a car by the side of the road can be tricky and uncomfortable, we wouldn’t blame you if you want to just get your car home first.

Common Causes Why a Car Dies While Driving

Before we learn how to diagnose a car that dies while driving, here are some of the most common causes you might want to know:

1. Bad Battery (and weak alternator)

This is quite a common issue. If your battery dies while it’s driving, it wouldn’t be able to feed electricity to a variety of important components, leading to your car shutting off while driving. For example, your engine needs the ignition system to create a spark to start the combustion process. The ignition system gets its energy from your battery, so if your battery dies, the ignition system will cease to work as well.

A flat battery takes no more than 15 minutes to change, and a fresh battery should cost no more than $200 even for the premium ones. Most batteries will last you bet 3 to 5 years, but they may go flat prematurely. This segues us perfectly to the second reason:

2. Bad Alternator

The alternator is in charge of charging your car’s battery as you drive along. If the alternator has gone bad, then it won’t be able to charge your battery properly. This then leads the battery to go flat even if it’s still new. We’ll discuss more how to diagnose an alternator below. If you have a bad alternator, often your car will show symptoms such as dimmed headlights or interior lights while idling.

If you do have a bad alternator, then replacement cost can be quite costly. Depending on your car’s make and model, a brand new alternator can cost between $300 – $7000. However, you can save some money by getting a remanufactured (or refurbished) one for around $200 – $300.

You can also save some money by doing it yourself thus eliminating the need for you to pay for labor costs. However, alternators will be a bit tricky to install since you need to attach the serpentine or drive belt onto it. If this is done incorrectly and there isn’t enough tension, your alternator won’t work properly. We don’t recommend doing this unless you know what you’re doing or a DIY enthusiast that’s willing to follow the proper steps.

3. Faulty Fuel Pump

A fuel pump is responsible for, well, pumping fuel into your engine. A fuel pump that has gone bad won’t be able to feed the needed amount of fuel to your engine, or worse, it won’t be able to do it at all. If this is the cause of your car shutting off, you will often notice your car jerking as you drive along.

Replacement fuel pump

Most fuel pumps are designed to last for up to 10 years, but for one reason or another, they may fail prematurely. The average replacement cost for a fuel pump is $450. However, the price varies between $250 – $1000 depending on your car make and model.

4. Faulty Mass Airflow Sensor

Your engine needs to take in air to start the combustion process in the engine. Within the intake system, your car has a mass airflow sensor (MAF) which tells your ECU how much air to put in. If this sensor goes bad, your car will take in the incorrect amount of air into the engine, disrupting the combustion process. In some scenarios, it can lead to the car shutting off. Similar to the fuel pump problem, you will notice your car jerking before it dies on you. A MAF will cost you around $450 to replace.

5. Bad Ignition Coils or Spark Plugs

Remember how your battery is needed to power the ignition coils and spark plugs? Well, these parts could go bad over time and causing your car to shut off. It’s not very common as cars with a bad ignition system usually struggle to turn on in the first place anyway. However, if your car is misfiring and then it dies on you, then you might have an ignition system problem. Most commonly with the ignition coils and spark plugs.

Spark plugs will usually need to be changed around 20,000 – 30,000 miles and should cost you no more than $10 to replace. While ignition coils will last for around 100,000 miles, and a set of ignition coils should cost no more than $450, including labor cost.

How to Diagnose a Car That Dies While Driving

If your car dies while driving, there are several possible scenarios. Paying attention to this could help you diagnose what’s wrong with your car:

1. Car Dies While Driving and There’s A Warning Light

How To Check If Alternator Is Bad Red Battery Icon No charge

If your car dies and you see a warning light on the dashboard, this can be one of two things. If you see a check engine light, then there’s something wrong with your engine. The problem varies from ignition coils to faulty air intake sensors, which you will need to determine by using an OBD reader to see the error codes.

Meanwhile, if you see a battery warning light, then the problem is related to your electrical system. Most likely it’s your alternator that has gone bad or the belt has snapped. An alternator is used to charge your battery with electricity as you drive along. If your alternator has gone bad, then the car is consuming more electricity than it is making. As a result, your battery will run flat and your car will shut off.

To check this, you will need a voltmeter to test your battery’s volt. A healthy battery should read at least 12.4 volts when the car is off. If you’re lucky and the car can start, a running car with a healthy alternator should register at least 14 volts. Any less than that then you have an alternator and battery issue.

What Else Should You Check?

If your battery warning light is on, here’s a few more things that you could check:

  • Check the battery terminals and connections. It’s not uncommon to find corrosion around the battery terminals and connections. Corrosion might cause the battery to be unable to charge properly, leading to a flat battery as you drive. A loose cable might also cause this.
  • Check the drive belt, since the alternator runs on the drive belt. If it’s loose, worn, or installed improperly then it could affect the alternator’s ability to charge the battery.
  • Check the electronic system circuit, including wires, connectors, fuses, and fusible links. See if there is damage to any of them, as this could affect the entire charging system.

You should also try to diagnose why your car won’t restart. If it’s caused by a flat battery, then you can still start your car again by using jumper cables with the help of a friendly passerby’s car. This will hopefully be enough for you to get to the nearest repair shop.

If your car can start again and it’s an alternator problem, we’d recommend driving without the A/C and headlights on (if you’ve broken down during the day, that is). Shutting off your car’s electrical components will prolong the battery’s life when you drive and should give you more juice to get home or to the nearest repair shop.

2. Car Dies While Driving and The Lights Cut Off

The root of this problem is largely similar to when your car dies and you see a check battery warning light. If your car shuts off and the electronic components are completely off, open your car’s hood and inspect your car’s battery. See if there are any loose cables or corrosion. You will need to tighten a loose cable or replace it if necessary. Meanwhile, corrosion on your battery’s terminals or cables can be cleaned by using a mixture of baking soda and water.

A faulty ignition switch might also cause this, but your headlights should still turn on. Another thing you might want to check is the fuse. If you have a blown fuse, some electrical components might still work but it’s preventing you from turning the car on.

3. Car Dies After Running for a Few Minutes

If your car starts just fine but then dies after a few minutes, you could be dealing with one of the following problems:

These components may fail as the car warms up after you turn it on. You can check a bad ignition coil yourself using either a multimeter or a spark tester, depending on the type of your ignition coil. As for the crankshaft position sensor, you will need a multimeter and you can watch the video below on how to test it:

4. Car Dies at a Full Stop or Idling

If you were driving just fine but your car suddenly dies as you reach a full stop, it could be caused by a faulty idle air control (IAC). The IAC is responsible for controlling your engine’s idling rotational speed. Over time, dirt may build up inside the IAC and jamming it closed, stalling your car while idling. Another common problem would be IAC’s circuit or solenoid has failed. You can learn how to check and replace your IAC in the video below:

What Else Should You Check?

If your car dies as you reach a full stop or when idling, there are a few more possible reasons. Another common problem is with the Mass Airflow Sensor (MAF). This sensor is responsible for determining the airflow rate that should enter your engine. A faulty sensor would mean your car’s Engine Control Unit (ECU) is feeding the incorrect amount of air. If your engine doesn’t get enough air, then it could stall.

Other possible causes include faulty manifold absolute pressure, engine coolant temperature, throttle position sensor, and intake vacuum leak. When these parts fail, you will most likely see a check engine light on the dashboard. If there’s a check engine light, you can easily pinpoint the problem by using an OBD reader and crosscheck the error codes. You can either buy an OBD reader for less than $500 or borrow one from your local repair shop or a friend.

5. Car Dies While Driving but It Can Start Again

This problem usually happens when there’s an issue with your fuel system. The possible causes are as follows:

  • Clogged fuel filter. A clogged fuel filter means your car is unable to feed the necessary amount of fuel to the engine. Most fuel filters are supposed to be changed every two years or 24,000 miles. Although they can last for up to 50,000 miles in some cars. Try to remember if you’ve had your fuel filter changed recently.
  • Faulty fuel pump. A faulty fuel pump would mean your car is unable to feed fuel to your engine properly. Most fuel pumps can last for up to 15 years, but they may fail prematurely. If your car jerks before it shut off then you might want to check your car’s fuel pump.
  • Bad fuel pressure regulator. Your fuel system needs pressure to operate, a faulty regulator means there isn’t enough pressure in the system. You will need a fuel pressure test kit to test this, and you can learn how to do it in the video below:

6. If Your Car Shuts Off Suddenly

In most of the scenarios above, you will notice signs before your car dies. Either a warning light on your dashboard may appear, a jerking or misfiring engine, or electrical components acting funny. However, if your car just completely shuts off out of nowhere as if someone has switched it off, you could be looking at these possible problems:

  • Faulty crankshaft position sensor or circuit.
  • Faulty ignition switch
  • Other faults in the ignition system, which includes the battery, ballast resistor, ignition control module, or ignition coil if your car has a single coil with a distributor.

If your car is completely unable to restart, then you may have a cable or a circuit that has completely failed. If your car can start again after it cools down, then you can troubleshoot by checking section 5.

How to Avoid Your Car Dying While Driving

A lot of the common causes can be avoided by simply taking proper care of your car. Most of the parts mentioned above are replaced regularly during a routine service. Here are some of our tips:

  • Remember to check your battery regularly. A good battery should register between 12.4 – 12.9 volts when the car is off and above 14 volts while idling. We would suggest every three months or so is enough, but monthly would be great. Additionally, you should also keep a lookout for damaged cables and corrosion.
  • Check your alternator if your car is over five years old or has done more than 150,000 miles. Alternators are supposed to last a long time, usually up to 150,000 miles. If your car has done more than that and you haven’t had your alternator replaced, it would be wise to check it regularly in anticipation.
  • Routine air filter maintenance. Normally, a dusty air filter won’t shut off your car entirely. At its worst, it will “only” cause your car to jerk or misfire as you drive along. However, leaving a dirty air filter uncleaned or unreplaced could shorten your MAF sensor’s lifespan. Be sure to replace your air filter when necessary, which is usually around 10,000 miles. They should cost you no more than $20 to replace.
  • Change your ignition coil and spark plugs. These are the two parts that need to be replaced regularly in your ignition system. Most of the other components should last quite long and you need not worry. Most of the time, your mechanic will notify you when it’s time to change the ignition coils and/or spark plugs.

Honda Civic Type R - Car Dies While Driving

Listen to What Your Car is Telling You

A lot of the time, your car won’t suddenly die on you and will show symptoms before it dies while driving. Listen to what your car is telling you and you can avoid having to deal with a car shutting off while you’re driving.

  • Check Engine or Warning Light. This one is fairly obvious and a very straightforward way for your car to tell you that there’s an issue. If you see this light, be sure to take it to diagnose it, you can do it yourself or do it at a trusted repair shop. This should be done immediately as there’s something wrong. If the check engine light flashes rather than lit continuously, you should stop driving immediately.
  • Dim interior or headlights. This would indicate that there’s something wrong with your car’s electrical system. It may be a battery, alternator, or fuse issue. If you see this, be sure to check your car’s electrical system to avoid further problems.
  • Car jerking as you drive. If your car jerks or misfires while you drive, then there’s a myriad of possible issues that we’ve listed down in a different article. In any case, a jerking car is not normal and you should check it to find out what the issue is. This way, you can stop the problem from getting more serious to the point where your car breaks down.
  • Colored smoke from your exhaust. Unless your car is a diesel, then the smoke it produces should be clear and mostly odourless. Thick white smoke from your exhaust indicates a serious problem and can lead to the car breaking down if not addressed immediately.

Car Dies While Driving Conclusion

Believe me when I say that having your car die on you as you drive along is an unpleasant experience and is a massive inconvenience. I used to drive a 1976 Mini Cooper and I think I had more breakdowns than trouble-free journeys. Anyway, hopefully, after reading this we’ve helped you understand better why your car died, how to diagnose it, and also the possible repair costs you might be facing.

Remember to safely take your car to the side of the road if it dies, you don’t want to be in the way of other drivers when your car dies. Also, as we’ve said, most cars will run smoothly over their lifetime and you can avoid this sticky situation simply by taking better care of your car. Remember to service your car according to its schedule, and look out for symptoms in your car. If you identify a problem early, you can avoid it getting more serious. Prevention is better than having to deal with a broken car, as they say. Or was it ‘prevention is better than cure?’ Well, in any case, prevention is better.

1 Comment

  • Zachary Tomlinson Says

    I’ve been thinking about purchasing a truck that I can use for my part-time job. I had no idea that a failing car ignition coil could become the reason why the vehicle would die without reason. I’ll keep this in mind and look for a repair expert for help when that happens.

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