Your car suddenly loses power while driving—now what?
It’s a frustrating and sometimes scary situation, but don’t panic. We’ll walk you through the most common reasons your car might lose power, what you can do in the moment, and how to prevent it from happening again.
Click through each section below to learn more about the causes, quick fixes, and when to call a mechanic.
If you are experiencing a loss of power in your vehicle and you need to have a professional look at it, contact the experienced and trustworthy experts at Hansma Automotive.
1. Common signs that you are losing power
If your vehicle suddenly "dies" while you're driving—meaning the headlights, dashboard lights, radio, and other electronics all shut off—it usually means that electrical power isn’t reaching critical systems.
If the engine also stalls, the ignition system is likely losing power too.
Watch for these common warning signs of electrical failure:
Dimming headlights while driving – A sign that your battery or alternator may be struggling to supply power.
Slow or difficult engine start – Your vehicle may hesitate or take longer to turn over.
Complete failure to start – The battery might be dead, or there's a break in the electrical circuit.
Electronics fading while driving – If the radio, dashboard lights, or power windows gradually stop working, it may indicate your alternator is failing or your battery is losing charge.
Sometimes this can just be a temporary failure, and the vehicle will all of a sudden begin to work again.
What to Do:
Start by checking your vehicle’s power sources. Inspect the battery terminals for corrosion or loose connections. If everything looks fine, it may be time to have your alternator and ignition switch tested by a professional.
2. What Causes A Power Failure & what to do
A) Bad Battery Connections
If you're losing power while driving, the first thing to inspect is your battery. Loose or corroded connections can disrupt the flow of electricity and cause your vehicle's electrical systems to fail.
1. Tighten the Terminals
Start by checking both the positive (+) and negative (–) battery cable connections. If either terminal is loose, use a wrench to carefully tighten it until it’s snug, but not overly tight to avoid damaging the terminal.
2. Clean Off Corrosion
Corrosion around the battery terminals can block electrical flow. If you see any white or greenish buildup:
Mix a small amount of baking soda with water.
Dip an old toothbrush into the solution.
Scrub the terminals and cable ends thoroughly.
Rinse with clean water and dry with a rag or paper towel.
Repeat until all corrosion is gone, then reconnect and tighten the cables.
3. Check the Cable Ends
Follow the battery cables to their opposite ends—typically the engine block (negative) and starter (positive). Make sure those connections are also clean and tight. Loose grounding can cause intermittent power loss.
B) Faulty Ignition Switch
The ignition switch is responsible for sending power to your engine and all of your vehicle’s key accessories—headlights, radio, power windows and locks, and interior lights. If the switch fails, power can be cut off to one or more of these systems, including the engine.
Signs of a failing ignition switch include:
The engine stalls while driving
If your ignition switch fails mid-drive, your engine may suddenly shut off. This is a serious safety issue and should be addressed immediately.The engine starts but quickly stalls
You may be able to turn the key and start your vehicle, but it dies within seconds. This typically means the ignition is supplying temporary power but can’t maintain it.
What to Do:
Checking the ignition switch is more complex than inspecting battery cables—it usually requires removing interior trim around the steering column or dashboard. While doing this, watch for signs of damage such as burnt wires or melted connectors.
If you’re not comfortable taking apart interior components, it’s best to take your vehicle to a trusted auto repair shop. If the ignition switch is indeed faulty, it will likely need to be replaced by a professional.
C) Bad Alternator
If your car has no power, it may be a sign that your alternator is beginning to wear out.
The alternator is responsible for keeping your battery charged and powering your vehicle’s electrical systems while the engine is running.
When the alternator stops working, your car runs entirely off the battery, and once that charge is depleted, everything shuts down.
Common signs of a failing alternator include:
Dashboard warning light – Often shaped like a battery, this may glow red or amber when the alternator isn’t charging properly.
Dimming or flickering lights – Headlights, interior lights, or dashboard illumination may behave erratically.
Dead battery – A failing alternator won’t recharge your battery, leaving you stranded.
Unusual noises – A growling or whining sound under the hood may indicate worn bearings or internal alternator issues.
Burning smell – You may notice the scent of burning rubber or hot wires, suggesting overheating or a failing belt.
What to Do:
Diagnosing alternator problems usually requires specialized tools like a multimeter or a charging system tester. It’s best to have a trusted mechanic inspect and test your alternator to confirm the issue.
3. Where Does Your Car Get Its Power From?
In today’s gas and diesel-powered vehicles, electrical power comes from two main sources: the battery and the alternator. These two components work together to keep your vehicle running and supply power to all its systems.
What Your Battery Does
The battery stores electrical energy and plays a key role in:
Starting the engine – It supplies the initial burst of power to crank the engine.
Running accessories when the engine is off – Lights, radio, and other features rely on the battery when the engine isn’t running.
Powering the alternator’s voltage regulator – This allows the alternator to properly control electrical output.
What Your Alternator Does
The alternator converts mechanical energy from the engine’s rotating crankshaft into electricity through a process called induction. While the engine is running, the alternator:
Generates power for electrical systems like headlights, windshield wipers, power windows, and your radio
Recharges the battery so it’s ready to start the vehicle again
Supports consistent voltage levels throughout the vehicle’s electrical system
What About Electric Vehicles?
Electric vehicles (EVs) don’t use alternators. Instead, they rely on a high-capacity battery and electric motor system that provides all the energy needed to power the vehicle and its accessories.
4. Why Your Car Has No Power Driving Uphill
Losing power while driving uphill is a common symptom of underlying vehicle issues. When your car struggles to accelerate on an incline, it could be due to more than just electrical problems—mechanical or fuel-related components may be to blame.
If your vehicle has faulty or clogged components, the engine will have to work much harder to maintain power under load, especially when going uphill.
In addition to the electrical issues covered earlier, check the following:
Fuel filter – A clogged fuel filter can restrict fuel flow to the engine, making it difficult to accelerate or maintain speed on an incline.
Exhaust system – A clogged catalytic converter or exhaust filter can prevent gases from escaping properly, reducing engine performance.
Air filter – If your air filter is dirty or blocked, the engine won’t get the airflow it needs to combust fuel efficiently, leading to power loss.
Important Safety Note:
If your car struggles to accelerate while climbing a hill, do not press harder on the gas pedal. This can overwork the engine, increase fuel waste, and potentially cause further damage. Instead, ease off and pull over safely to assess the issue or call for assistance.
5. Why Your Car Has No Power When Pulling Away
If your car feels underpowered even while driving on a level road, it’s a sign that something isn’t functioning properly under the hood. While electrical issues could still be the cause, other mechanical or sensor-related problems may also be at play.
Here are some common causes of power loss on flat terrain:
Mechanical Issues
Low engine compression – Reduces your engine’s ability to generate power efficiently.
Clogged fuel filter – Restricts fuel flow, leading to sluggish acceleration.
Dirty air filter – Limits airflow into the engine, which reduces combustion efficiency.
Blocked exhaust manifold or catalytic converter – Prevents exhaust gases from exiting properly, reducing power.
Faulty Sensors
Modern engines rely on a network of sensors to operate efficiently. If any of the following sensors fail, engine performance can drop:
Camshaft position sensor
Crankshaft position sensor
Mass air flow (MAF) sensor
Oxygen (O2) sensor
Failing Actuators or Components
Fuel injectors – If clogged or malfunctioning, they may not deliver the correct fuel mixture.
Fuel pump – A weak or failing pump won’t deliver enough fuel under load.
Spark plugs – Worn or fouled plugs reduce combustion efficiency.
Driving in Hot Weather?
Your air conditioning system draws power from your engine. If you're driving in high temperatures with the A/C on full blast, you may notice reduced performance, especially in smaller vehicles or those with older engines.
6. What to Do When Your Car Has No Power? Contact a Reliable Mechanic
If your vehicle is experiencing power loss, it’s important to have it diagnosed and repaired as soon as possible. But just as important is finding an auto repair shop you can trust—one that will provide honest recommendations and only perform the repairs you actually need.
At Hansma Automotive we take pride in being that trusted partner for drivers in Kitchener-Waterloo. With a 4.8-star rating on Google Reviews, we’ve built our reputation on quality work, transparency, and friendly service. We service all makes and models and offer a full range of auto repair solutions.
Our loyal customers continue to refer friends and family, making word-of-mouth our biggest source of new business.
Check out our reviews for yourself and see why Hansma Automotive is one of the top-rated and most trusted auto repair shops in the region.
Other Great reasons to choose Hansma
When it comes to auto repair, you deserve a shop that offers expert service, fair pricing, and genuine care. Here’s why Hansma Automotive continues to be a top choice for drivers in the Kitchener-Waterloo region:
Competitive Pricing: Whether you need a new battery, alternator, ignition switch, or any other repair, our highly trained technicians will diagnose and fix the issue at a fair, competitive price.
Reliable Repairs: You can count on our skilled and friendly staff to deliver quality repairs that keep your vehicle running safely and efficiently.
Over 33 Years of Service: Hansma Automotive has been proudly serving the Waterloo region since 1987, earning a reputation for excellence in automotive care.
Locally Owned and Operated: We’re a family-run business, rooted in the community. Supporting Hansma means supporting local.
True Customer Care: At Hansma, we treat every customer like family. From the moment you walk in, our goal is to provide honest advice, respectful service, and dependable care.