There are fewer things scarier—and more dangerous—than cruising down the highway and having your GMC Sierra suddenly turn off.
I understand firsthand what a time and financial inconvenience this can be, so I’m here to help you sort through this problem.
Why Does My GMC Sierra Turn Off While Driving?
Your GMC Sierra might turn off while you’re driving because of something as simple as it ran out of gas or you need to change the key fob. Alternatively, it could be a more complex problem such as a dead v12 battery, a faulty fuel pump, or an issue with the sensors.
I’ll help you sort through the numerous reasons why your Sierra turned off while driving.
Furthermore, I’ll share tips at the end of this post to help you prevent it from happening again.
Reasons Why Your GMC Sierra Turns Off While Driving
Here’s the good news: When your GMC Sierra shuts down when driving, it’s not always a sign that you have a significant issue on your hands.
Let’s explore the many reasons why this might be happening, starting with the least severe problem.
You Need to Fill Up Your Gas Tank
Running out of fuel is one of the most common reasons any vehicle turns off while driving.
So, if you’ve been ignoring your gas gauge for a few miles too long, take a look at it.
However, the driver isn’t always to blame—if a fuel gauge is off-kilter, it may report more gas in a tank than there actually is.
If you run out of gas, the best-case scenario is being near a gas station.
But even if you aren’t, it’ll likely end up running you less money to get yourself out of the situation than many of the scenarios we’ll be talking about shortly.
Dead Key Fob
Whereas it’s easy to keep track of your vehicle’s gas levels, it’s common for people to forget about the battery in their key fob.
Without a working key fob, your GMC Sierra will shut down.
To figure out if your key fob is the culprit, press any of its buttons.
Do you see its light illuminate? If not, it’s time to change the battery.
It’s wise to keep a flathead screwdriver and backup battery in your Sierra for situations like this.
Battery Cables Need Cleaning
Pull out the rags in your trunk and roll up your sleeves—your GMC Sierra might turn off when you’re driving because of dirty battery cables.
Luckily, this problem has an easy fix.
Simply inspect the cables around the battery and remove any debris that might be preventing them from having a strong connection.
If you see a lot of rust, it might be time for new parts.
Furthermore, check that the battery cable bolts are secure.
If not, simply tightening them up could get your Sierra running again.
Faulty Fuel Pump
Your GMC Sierra has an engine computer that monitors how well things are working, alerting you when something is wrong.
However, the computer usually doesn’t monitor the fuel pump, making it easy for a long-term issue to occur, resulting in your vehicle turning off mid-drive.
Since your vehicle is off, try turning the key.
Do you hear a whining noise? If so, your fuel pump is working. If not, it’s time to get your vehicle towed to the nearest repair shop.
Problem With Chassis
Another engine-related issue why your GMC Sierra might shut off when driving is because there’s an issue with the chassis connection.
As a result, your Sierra might misfire.
Before it shut down during your drive, you also might have noticed it having slower starts.
These issues often occur because of a corroded cable to the chassis and require a mechanic’s intervention to resolve.
Dead 12v Battery
The GMC Sierra runs off a 12v battery.
Normally, this battery gets recharged when you drive.
However, if you have an alternator that isn’t correctly fueling it, your vehicle could shut off when you’re driving it.
Furthermore, your Sierra’s 12v battery needs replacing every three to five years.
So, if you’re behind schedule, this could be a reason that you’re not able to start your truck.
In either case, you should notice a warning light on your truck’s dashboard if the alternator isn’t recharging your 12v battery.
So, if you know that such a light didn’t come on, you’ve likely got a different issue on your hands.
Sensors Not Reporting Data
Increased technology has many benefits for vehicle owners, but it can also cause its own set of issues.
In the case of the crankshaft and camshaft sensors, if they don’t report their revolution status to the engine, your vehicle may shut off.
Another sensor-related problem that can stop a moving GMC Sierra is the mass airflow sensor.
However, you’ll likely know in advance that something is wrong with the airflow sensor; it’ll spark a trouble code to your dashboard.
Clogged Fuel Filter
A clogged fuel filter can suddenly cause your GMC Sierra to shut off while you’re driving.
Many situations can cause a clogged filter, including:
- Sediment from fuel
- Rust from an old fuel tank
- Moisture in the fuel tank
- Grimy air filter
Regardless of the cause, you can either clean and reuse the fuel filter or replace it altogether.
You should then be able to get your Sierra back out on the road.
Often, you’ll know that you have a broken starter before you begin driving.
However, sometimes the starter can create issues when you’re in the middle of the drive, particularly if oil soaks it.
Another sign that you might have a starter issue when driving is if you see smoke coming from your car.
In many cases, GMC Sierras shut off when driving because of something electrical-related. Blown fuses and short circuits are examples that can cause smoke to form.
How to Prevent Your GMC Sierra From Shutting Off
Let me start with this—a Sierra owner can go above and beyond to care for their vehicle, and they can still experience it turning off when they drive.
However, there are some times you can do to prevent this scenario from happening, including:
- Keeping your fuel topped up
- Setting a calendar reminder to change your key fob battery
- Clean the battery cables
- Check the battery bolt tightness
- Clean your fuel filter regularly
What If My GMC Sierra Still Doesn’t Turn On?
In almost all cases, a GMC Sierra will shut off because of something related to a faulty electrical connection.
So, if you’ve done all you can on your end to analyze the various scenarios above and you still can’t get to the bottom of the problem, it’s time to take your Sierra to a mechanic.
The Bottom Line
GMC Sierras are normally smooth-running vehicles.
So, if your Sierra shuts off when you’re driving, it’s not necessarily an indication that you need to invest money into another car.
Instead, something as cheap and easy as changing out your key fob battery can get your vehicle continuing down the road.
Nevertheless, there are situations when your Sierra may shut off while driving for more serious reasons.
In these cases, it’s essential to get your truck to the nearest repair shop.