Car Shuts Off While Driving: 11 Causes and How To Fix It

Driving is commonly seen as a peaceful and unwinding experience, offering a chance to escape the demands of a hectic schedule. Nevertheless, this calmness may quickly turn into frustration when your car begins to produce different drivability issues, such as unusual noises, uneven braking, or even more severe problems that might cause your car to shut off while driving. Are you also thinking about why your car shuts off while driving?

Owning a vehicle comes with the responsibility of proper maintenance. Unfortunately, some drivers treat their vehicles as if they run on magic, neglecting essential inspection and maintenance. To ensure the good health of your car for the long haul, you need to regularly check your engine coolant, fuel, and oil, other vital components.

The new vehicle models are equipped with various sensors and devices to ensure the smooth operation of the engine. Having a basic understanding of your car may be immensely helpful in addressing simple issues, like the car shutting off while driving. But what could be the reasons behind such an incident?

The most frequent causes a car shuts off during driving are a bad fuel injector, a faulty crankshaft position sensor, or insufficient fuel in the engine. Additionally, a bad spark plug, ignition lock, or faulty alternator can also trigger such an issue.

This article explains the most common reasons why a car shuts off while driving and how to fix it.

Reasons Why A Car Shuts Off While Driving

A car shuts off while driving due to different reasons such a bad crankshaft position sensor, an issue with the ignition system, a dead battery, a faulty alternator, empty fuel tank or a faulty engine sensor.

Let’s discuss the causes of a car to shut off while driving:

1) Bad Crankshaft Position Sensor

One of the major causes a car shuts off while driving is often attributed to a malfunctioning crankshaft position sensor. This vital component is critical for the proper operation of the vehicle engine.

The crankshaft position sensor plays a crucial role in monitoring the motion of the crankshaft and helps the vehicle’s main computer to adjust the precise ignition timing and fuel injection rate.

When this sensor becomes defective, it fails to accurately detect the position of the crankshaft, leading to engine misfiring and, ultimately, causing the car to die while driving.

Signs of a faulty crankshaft sensor include misfiring, a reduction in overall performance, poor fuel efficiency, a rough-running engine, engine stalling, and other related issues.

Additionally, a malfunctioning sensor may cause irregular readings on the tachometer. If you connect an OBD-II scanner, you may also encounter diagnostic trouble codes P0335 and P0338, which indicate problems with the crankshaft position sensor.

2) Dead Car Battery

If your car dies while accelerating, it’s essential to check the health of your car’s battery. If the battery is not the issue, it could be caused by unnecessary parasitic loads.

Frequent battery drainage or difficulty starting the vehicle, after it has been sitting idle for a while, may indicate a parasitic drain issue. This indicates that something in the vehicle is consuming your battery power even when the engine is turned off.

3) Empty Fuel Tank

Checking your fuel level while accelerating is something many owners are familiar with. Having an accurate fuel level sender or fuel gauge is crucial, as a faulty one can lead to significant issues.

To check if your fuel level sensor or fuel gauge is functioning correctly, you can try filling 1 gallon (4 liters) of fuel and see if it registers properly.

4) Bad Fuel Pump or Fuel System

The fuel pump in your car is responsible for providing the right amount of fuel to the engine. When the fuel pump stops working correctly, your engine may shut off while driving, leaving you stuck on the road.

Unfortunately, there’s no way to bypass a bad fuel pump, so you’ll need to either repair it or replace it.

Another possible cause for the engine shutting down may be clogged fuel filters, which block the fuel flow to the engine.

The main function of the fuel filter is to clean the fuel before it reaches the engine. When it gets blocked, it restricts the fuel supply, causing your car to die. The good news is that replacing a fuel filter is a straightforward task.

In many vehicles, the fuel pump is located within the fuel tank. A trick used by many professionals is to give the gas tank a gentle kick with their foot or something similar when the car shuts off while driving. If your engine turns on again after the kick, it’s a sign that the fuel pump might be the issue.

However, caution must be exercised not to knock the fuel tank with something sharp, as fuel tanks are typically made of plastic, and causing a hole in them would be highly undesirable.

5) Bad Ignition Switch

A potential reason for a car shutting off while accelerating is a faulty ignition switch. This switch is situated just behind the ignition lock. It activates as you turn the key to switch on the engine.

Over time, corrosion and rust can accumulate on tiny metal plates inside the switch, causing a loss of connection and resulting in the entire ignition system of your car being turned off.

As a consequence, the car will die abruptly. Checking for any remaining lights or ignition indicators on your dash when the vehicle shuts off can help identify a bad ignition switch.

6) Faulty Alternator

The alternator plays a vital role in managing your car’s electricity supply. When it malfunctions, it can result in a car dying suddenly while driving. A bad alternator cuts off the supply of electricity to essential vehicle parts, leading to dashboard lights switching off or the engine suddenly starting to lose power.

One of the primary symptoms of a failing alternator is the red battery light on your dashboard, illuminating intermittently.

If your car has enough electrical power and the starter motor works fine after it shuts off while driving, the problem might not be with the alternator. In such cases, you’ll need to do further investigation to figure out what’s causing the issue.

Read More: Bad Alternator Symptoms and Causes

7) Bad Spark Plugs 

A spark plug plays a crucial role to ignite the air/fuel mixture within each engine cylinder. If a spark plug becomes faulty, it may lead to a sudden engine stall, causing the car to die while driving. To prevent this issue, it is essential to conduct periodic visual inspections to check for any defects.

In addition to visual checks, be vigilant for signs of potential problems, such as misfires, engine knocking, poor fuel economy, or a decrease in performance. Recognizing these signals early on and addressing them promptly is crucial in preventing unexpected engine shutdowns while accelerating.

8) Faulty Sensors

The new vehicle models are equipped with various sensors that help to regulate the fuel injection rate and ignition timing to optimize fuel economy. If any of these sensors fail or don’t work properly, it can lead to the complete shutdown of the car engine.

If your car shuts off while driving but starts back up afterward, or if it dies when slowing down or idling, it indicates an issue with an engine sensor.

Incorrect readings from sensors like the Mass Air Flow (MAF) sensor, Coolant Temperature sensor, or Oxygen sensor can disrupt the air-fuel mixture or idle RPM, potentially causing the engine to stall. However, in most cases, these sensors alone cannot completely shut off the engine.

9) Bad Throttle Body

A clogged or bad throttle body can also force your car to shut off while accelerating. The throttle body is a crucial engine component that regulates the supply of air and fuel to the engine, thereby controlling the engine’s power output.

Positioned between the engine and the gas pedal, the throttle body responds to the pressure on the gas pedal, opening up to allow more air and fuel into the engine cylinder, increasing the engine’s power output.

Additionally, in the vicinity of the throttle body, you’ll find the throttle position sensor (TPS), an electrical sensor that sends important data about the throttle body to your vehicle’s ECM or PCM to help manage engine performance.

10) Damaged Timing Belt

A failing or slipping timing belt can be caused by various factors, such as a weak drive structure, misalignment, under-tensioning, worn pulleys, or extreme load on the car.

Regardless of the cause, if the timing belt fails, it can stop the operation of the camshaft and result in an abrupt engine shutdown while driving. This situation is one that drivers would definitely want to avoid, as it can often lead to severe engine damage.

11) Bad Engine Control Module (ECM)

A malfunctioning Engine Control Module (ECM) can cause a car shuts off while driving. The ECM is responsible for receiving data from different sensors and adjusting the vehicle’s performance accordingly to suit driving conditions.

For example, if your vehicle’s coolant sensor is faulty and provides inaccurate readings of engine temperature, the ECM may shut off the car to prevent overheating and potential damage.

Several other sensors can also contribute to this issue, including the manifold absolute pressure sensor, mass airflow sensor, throttle position sensor, oxygen sensor, and fuel pressure sensor.

If any of these sensors become faulty and provide incorrect information to the ECM, it can cause your engine to switch off unexpectedly while accelerating.

How To Fix A Car That Shuts Off While Driving

As discussed above, there are various reasons for a car to shut off while accelerating. You need to replace or repair one or more of the below-given parts to fix a car that shuts off while driving:

1) Check Trouble Codes

In the old vehicles, diagnosing vehicle issues often required using a multimeter or relying on intuition to pinpoint the issue. Thankfully, modern vehicle models come equipped with advanced diagnostic software that has the ability to detect engine sensor problems and store corresponding error codes, triggering the check engine light.

This technological advancement has significantly simplified the diagnosis process. Instead of manually inspecting each engine sensor, you can now access the engine control module (ECM) or Powertrain Control Module (PCM) to retrieve stored trouble codes using an OBD-II scanner.

You have the option to purchase your own scanner or take your vehicle to a service shop where they can read the codes stored in your vehicle’s ECM memory.

Once you have the trouble codes, you can proceed with troubleshooting based on the information provided by the diagnostic scanner.

For instance, if the scanner shows a misfire error code, potential causes could be related to a problematic ignition coil, a faulty spark plug, or issues within the ignition system.

By knowing the specific error code, you may easily address the main issue, avoiding unnecessary part replacements and ensuring a more effective and efficient repair process.

2) Check Alternator Voltage

If you lack an OBD-II scan tool or there are no stored error codes, the next step is to check the alternator voltage while the engine is operating. Follow the below-given steps to check the alternator voltage:

• Press the emergency brakes and turn on the engine.
• Use a multimeter to measure the car battery voltage.
• If the multimeter reading is less than 12.5 volts, it indicates an issue with the car’s alternator or charging system.

3) Add More Fuel

As discussed above, insufficient fuel is one of the major causes for a car shuts off while driving. Despite it appearing obvious, it’s important to ensure that your fuel tank has an adequate amount of fuel.

Sometimes, you might unknowingly be running low on fuel, and this can lead to engine stalling, especially during steering at higher speeds. The reason behind this is that a low fuel level can cause the fuel pump to draw in air instead of fuel.

There is a possibility that the fuel gauge sensor is bad, causing inaccuracies in the fuel level reading.

To rule this out, it’s wise to open the fuel cap and add a little fuel to see if it resolves the stalling issue. This simple check can help prevent potential complications related to low fuel levels or faulty fuel level sensors.

4) Check The Dashboard

When your car shuts off while driving, you should also inspect your vehicle’s dashboard lights.

If you observe that the dash lights don’t work as your engine stops operating, it could specify an issue with the ignition switch.

However, it’s important to consider that this symptom may also be triggered if your battery has insufficient voltage because of a faulty alternator. Therefore, it’s crucial to check both the alternator and the ignition switch if this issue arises.

5) Check The Tachometer

In many cars, the RPM meter or tachometer relies on data from the crankshaft position sensor.

If you experience a situation where the RPM meter doesn’t work when your car shuts off while driving, or it remains stationary when you turn on the engine, it might indicate that there’s an issue with either the camshaft position sensor or the crankshaft position sensor. These sensors play a critical role in the engine’s operation, and any malfunction can lead to stalling or other performance issues.  

6) Measure Fuel Pressure

Your car shuts off while driving due to low fuel pressure. Therefore, it’s important to check the fuel pressure in the vehicle. The recommended method is to attach a manual pressure gauge to the fuel rails or fuel lines.

Alternatively, if your vehicle has a fuel pressure sensor, you may utilize a diagnostic scan tool to check the fuel pressure.

However, be aware that there’s a possibility that this sensor may be faulty, leading to inaccurate readings. To proceed with this method, refer to your owner’s manual for the correct fuel pressure values. If your vehicle has insufficient fuel pressure, it’s crucial to inspect the fuel pressure regulator, fuel pump, and fuel filter for potential issues.

7) Check Sensor Data

If you have checked for fault codes in the Engine Control Module (ECM) but haven’t found any stored, and the issue persists, the next course of action is to use an On-Board Diagnostic (OBD) test to monitor data coming from all engine sensors.

To accomplish this, you’ll require a diagnostic tool that is ideal for your vehicle’s ECM. However, it’s worth noting that understanding the readings from the engine sensors can be challenging. To interpret the data accurately, you’ll need to refer to your vehicle’s service manual or obtain the specifications for your specific car model.

8) Contact A Professional

If all the troubleshooting steps mentioned above have been attempted, but the issue is still there, it is advisable to get assistance from a mechanic. While this may involve some costs, enlisting the help of someone experienced in handling such issues can be a prudent decision.

How To Avoid Car Shutting Off While Driving?

• Ensure the proper maintenance of your vehicle.
• Properly check the fuel level in the fuel tank before driving.
• Fix the minor issues instantly before they cause expensive repairs.
• If your car is experiencing difficulties during startup, it could indicate issues with either the fuel pump or the fuel filter.
• When you notice a faulty sensor or faulty part, try to repair or replace it as soon as possible.
• Keep an eye on the gas cap gasket’s condition, as a worn-out gasket can reduce your car’s fuel efficiency and cause your car shuts off while driving.

FAQ Section

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