Can A Bad Alternator Cause Loss Of Power [Explained]

We all know that your car battery is directly dependent on your alternator. But can a bad alternator cause loss of power?

Yes, a bad alternator can cause a loss of power. When the alternator stops working or not working as it’s supposed to, the battery doesn’t get charged. Slowly the battery gets drained by your car’s electric system, which consists of various sensors and other crucial components.

can a bad alternator cause loss of power

When the battery is low on charge, the sensors start malfunctioning causing a loss of power. Similarly, when an alternator is overcharging the battery, it gets damaged, which also results in a loss of power.

In this article, we will be relating the power loss of your car to a bad alternator. Also, how a bad alternator can cause different problems.

How Can A Bad Alternator Cause Loss Of Power

The electrical motor, sensors, voltage regulators, and fuel pump all are dependent on the power that the battery supplies. And the battery relies on the alternator as it is the sole component in the vehicle that charges the battery. 

car bad alternator

So, if you have a bad alternator, the battery won’t get charged properly. As a result, all the electrical components in your car will start fluctuating causing a loss of power.

The alternator also powers the electrical components when you drive the vehicle. So, a bad alternator won’t be able to power the electrical system properly and your car will experience a power loss.

That’s not all, once your battery is completely drained, the electrical system will shut off and you won’t be able to start your car. 

What Are The Symptoms Of A Bad Alternator

The symptoms of a bad alternator include-  

  • Battery Warning Light: If your alternator is underperforming, the first thing you should look for is the lit-up battery light on your dashboard. The battery light usually lights up when the battery voltage is lower than it’s supposed to be. This can be caused by a faulty alternator.
  • Dimmed or Extra Bright Headlights: When your car’s alternator starts to go bad, it can mess with the power supply to your electronic accessories. That means you might notice some weird behavior from things like your headlights, which might be too dim or blazingly bright. 
  • Dead battery: A dead battery is the most common and obvious sign of a bad alternator. The alternator charges the battery as you drive your car. If you have a dead battery, it could mean that the alternator is not doing its job.
  • Trouble Starting: Have you ever tried starting your car, only to hear a clicking sound instead of the usual engine purr? This may be because the battery is low on voltage. It could be a sign that your alternator isn’t charging the battery properly. 

But will a bad alternator cause the car not to start? Well, yes, if the battery is completely drained. 

  • Stalling: A bad alternator can cause stalling in your vehicle. Frequent stalling is another sign that your alternator is failing. This happens when the spark plugs do not get enough power from the alternator. 
  • Failing Accessories: Your windows might roll up or down more slowly, and your seat warmers or AC might feel different than usual. Even your speedometer and other instruments could start acting up.
  • Strange Noise: When the serpentine belt is misaligned, it may rub on the alternator’s body, creating a weird noise. This causes the alternator to fail creating a weird sound in the process. But what does a bad alternator sound like? A bad alternator makes a whining or growling sound, something like this-
  • Burning Smell: If the serpentine belt is not misaligned, but rather damaged or worn out, it can emit a burning smell. The belt is always under tension while the car is running. That’s why the belt is prone to damage or cracks.

What Other Problems Can A Bad Alternator Cause

The alternator is in charge of charging the battery, thus controlling the whole electrical system of your vehicle.

That’s why, other than causing a loss of electrical and engine power, it can cause several issues. Let’s take a look at what those problems are-

Can A Bad Alternator Cause A Loss Of Acceleration

Yes, a bad alternator can indirectly cause a loss of acceleration in your vehicle. If the alternator isn’t generating the correct voltage, the vehicle’s ECM may malfunction. The ECM is responsible for regulating various engine functions, such as fuel injection and ignition timing.

When the voltage supplied by the alternator isn’t correct, the ECM will struggle to operate, resulting in a malfunction in the fuel system or different sensors, ultimately affecting acceleration.

Can A Bad Alternator Cause Loss Of Power Steering

Yes, a bad alternator can cause a loss of power steering. The power steering pump relies on hydraulic pressure to assist with steering.

If the alternator fails to supply the necessary electrical power to the vehicle, the power steering pump will fail. As a result, you will lose the hydraulic pressure needed to steer your vehicle.

Can A Bad Alternator Cause AC Problems?

Yes, a bad alternator can and will cause AC problems. The AC relies on the battery for power to operate. A bad alternator will cause the battery to go bad making the AC inoperable.

Check out our guide on the alternator causing AC problems to learn more about this issue.

Can A Bad Alternator Cause Sputtering

Yes, a bad alternator can cause sputtering in your engine. This is because the alternator is responsible for providing power to your spark plugs, which ignite the air and fuel in the combustion chamber.

When the alternator is going bad, it may not be able to send enough power to the spark plugs, resulting in misfires and sputtering.

Does Bad Alternator Affect RPM

Yes, a bad alternator can affect RPM but it is highly unlikely. RPM is mainly affected by other factors such as a dirty or faulty throttle body, clogged air filter, or malfunctioning spark plugs. 

Can A Bad Alternator Cause False Codes

Yes, a bad alternator can cause false codes in your vehicle. All of the electrical system is dependent on the alternator for power. So, when it malfunctions, the sensors and other electrical components will too, resulting in error codes.

For instance, a bad alternator it can cause the oxygen sensor to record incorrect readings. This can lead to trouble codes related to the engine’s fuel-air mixture. 

Can A Bad Alternator Cause Transmission Problems

Yes, a bad alternator can cause transmission problems. The reason for this is that the transmission is controlled by the vehicle’s computer, which relies on a steady supply of power from the battery and alternator.

If the power supply is disrupted, it can cause the computer to malfunction and affect the transmission’s performance.

Visit our guide on the alternator causing transmission problems to get a complete picture of why it happens and how you can solve it.

What Other Problems Can Cause a Loss of Power

If your car does not show any signs of a bad alternator, but you still feel like it is not running well; here are some insights on what went wrong with it.

i. Clogged Fuel Filter

The fuel filter’s job is to filter out impurities from the fuel before it reaches the engine. If the fuel filter is clogged or dirty, then these impurities can reach the engine. This can lead to a loss of power in your car.

Replacing the clogged fuel filter will solve the power loss issue.

ii. Clogged Exhaust

Over time, the exhaust can become clogged with debris. That’s because the exhaust system is responsible for carrying exhaust gases away from the engine. When the engine is not able to expel the gases it can cause a loss of power.

If your exhaust is clogged you can simply check what’s blocking it and clean that up to fix the problem.

iii. Mass Airflow Sensor Problem

The MAS measures how much air is flowing into and out of the engine. This sensor will not be able to communicate with the engine how much airflow is coming in and out if there’s a problem. This can lead to a loss of power in your car.

A faulty MAF sensor is irreparable, so you will have to replace it.

iv. Spark Plug Problem

If there’s an issue with the spark plug, then it won’t be able to ignite the fuel, causing a loss of power in the engine. Routine checks or replacements can easily prevent this from happening.

Spark plugs are usually very cheap, so replacing them is not a big deal. However, if the plug is corroded, cleaning it would suffice.

v. Compression Problem

When the compression in the engine’s cylinders is too low, then the engine won’t be able to generate the required power. This will eventually cause a loss of power. When that happens, it’s best to consult with an expert.

vi. Fuel Pump Problem

If your car’s fuel pump is weak or malfunctioning, then the engine won’t receive enough fuel to operate efficiently. As a result, you will experience a significant loss of power. 

Diagnosing a fuel pump issue can be complicated. so you should take your car to a mechanic.

vii. Air Filter Problem

The air filter’s job is to ensure no impurities are mixed into the engine with the combustion air. If impurities do manage to get through, it can cause a loss of power. Just replacing the air filter is enough to solve this problem.

viii. Carbon Buildup on Fuel Injectors

Over time, carbon can build up on the fuel injectors making it difficult for the injectors to spray fuel into the cylinders.

Because of this, a loss of power occurs. Using a premium quality engine oil additive can clean up excess carbon buildup.

ix. Oxygen Sensor Malfunction

A malfunctioning oxygen sensor will cause the engine to burn a rich air-fuel mixture. When that happens, it reduces fuel economy and causes a loss of power. 

Oxygen sensors must be replaced if they are malfunctioning.


Can You Jumpstart A Car With A Bad Alternator? 

Yes, you can jumpstart a car with a bad alternator, as long as the battery has enough charge to keep running. But you will have to keep jumping it if you do not replace the alternator.

How Long Will A Car Run With A Bad Alternator? 

A car can run for about 25-30 minutes with a bad alternator if the battery is fully charged. Once it stops, you wouldn’t be able to start it again. 

How Long Do Alternators Last?

The typical lifespan of an alternator is between 80,000 and 150,000 miles or about seven years. But it depends on how you are taking care of it. With proper care and maintenance, it may be possible to extend its lifespan even further.


So, can a bad alternator cause a loss of power? Yes, it can as well some other serious issues. 

So, if you have a bad alternator or having performance issues, you should try to find the issue ASAP and fix it. Holding back with the repair will only make the issue worse and cause further or even irreparable damage.

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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