Why Won’t My Toyota Prius Start?

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Hybrid cars like Toyota Prius are known for having outstanding fuel economy.

Considering how the international oil prices are increasing with every passing second, the trend has shifted towards purchasing Hybrids.

Toyota Prius is an amazing car and got so many features, but the comfortable leather seats and huge cargo space often catch the attention of potential buyers in the hybrid market.

Hybrid cars tend to work differently from normal cars. This is why maintaining these cars and keeping the engine in check might be difficult.

In some cases, the car might bail on you, and you would be seen searching for answers to, why won’t my Toyota Prius start?

Find out the reasons below:

  1. Defected Key Fob
  2. Excessive Engine Oil
  3. Imbalanced Voltage In Battery
  4. Faulty Ignition
  5. Major Security Issues

These are the most common problems in case your Toyota Prius fails to start.

If you want to know more about these issues, keep reading the article as you will also find the solutions for these issues.

What Would Cause A Toyota Prius To Not Start?

Do you know how to force starting your Toyota Prius if there are some issues with the vehicle? Read my guide to find out

Toyota Prius is a car that provides fuel efficiency and spacious cargo space. It is more family oriented than other rival hybrid cars.

Now, if a car has such a long list of features that do not mean it will not face any issues in the future.

Every car tends to undergo certain malfunctions, and Toyota Prius is no exception in this case.

The problems I have listed above require in-depth analysis and insights to be understood clearly. Let’s discuss them in more details.

1: Defected Key Fob

Many vehicles use a Power button rather than an ignition key to start the engine. A key fob is a compact remote-control device used to operate a keyless entry system.

You can praise the small but powerful key fob when you click the button on the keys and hear the soft beep of your car’s unlocking feature.

However, at times, the key fob gets defective. The key fob can get damaged due to multiple reasons.

For example, there are batteries in a Toyota Prius’s key fob. Those batteries might have drained, or maybe the fuse near those batteries has blown.

Sometimes, there is a chance that the wiring of the key fob might be altered. Your car’s sensors might not be getting the signals from the key fob.

Every key fob has a useful life of three to four years, after that, the battery slowly but gradually starts to drain and die. The sensors tend to get faulty with time as well.

What Should You Do About It?

  • Replace the battery of your Toyota Prius’s key fob. This is not that expensive, considering that the key fob is just a small component that helps your car start.
  • Keep your new key fob away from water, moisture, or rust. Dust and debris can damage the key fob to a great extent.
  • Check to see if your car’s sensors are working fine or if they are at fault for catching signals from the key fob.

2: Excessive Engine Oil

Air and fuel are the main ingredients for any engine. However, the engine oil is necessary for the combustion process to start.

The oil sent to the engine needs to be of a certain quantity. If it is lower than that amount or more than the desired quantity, the combustion process might not start.

One tends to get the oil changed from different service stations. At times, excessive oil enters the combustion chamber as a result of over-filling.

You might be wondering that different models of Toyota Prius would require different quantity of oil. On average, around 4 quarts of oil are required for Toyota Prius.

If the oil in the engine exceeds this limit, the combustion process would be tampered and your car would not start.

Moreover, at times, the viscosity of the oil that you are inserting into your Prius might vary.

The manual of your car would tell you which oil to use, the type of viscosity that it demands, and the quantity of oil to put in.

What Should You Do About It?

  • Carefully read your car’s manual when you purchase a new Toyota Prius.
  • Tell the person filling your car’s oil about the desired quantity. Make sure you supervise them throughout to stay away from scams.
  • Do not try to integrate low-quality oil of different viscosity with your Toyota Prius. It would impact the performance of your engine.

3: Imbalanced Voltage In Battery

Having a battery trouble is another common problem. Since your hybrid car has two batteries, one of them is most likely to blame.

The 12v battery terminals will be our first focus because they are the most straightforward to identify and fix.

Check them out carefully to determine if corrosion is making it difficult for them to transfer power from one point to another.

If your battery is undamaged, corrosion will manifest as white or green deposits that can be cleaned off.

If the charge provided in the battery is lower than 12v or higher than a certain level, it can cause the battery to drop dead or malfunction.

This would lead to your car not starting. One of the batteries in your Toyota Prius might be getting a charge too high while the other might be getting too low.

In this case, you can blame your alternator.

What Should You Do About It?

  • Battery in a hybrid car works best with high voltage. You should not try checking the battery. Instead, ask a professional to help you out.
  • Provide sufficient airflow to your battery as that would help your battery in operating efficiently. It helps to keep the temperature between important cells to an adequate level.
  • No matter which car of Toyota you are using, you must take your car to the service station semi-annually.

4: Faulty Ignition

Faulty ignition is one of the most typical problems when it comes to starting issues. The engine will not start if no spark is produced.

A major reason is faulty or misplaced spark plugs. You can see that ignition regulates practically every part of your vehicle’s operation. Thus it must function optimally.

Power is transmitted from the ignition switch to the starter gear, engine settings, and control mechanisms.

If the ignition is malfunctioning, these systems might not get the power they require to start.

Furthermore, this may also refer to be a battery problem when your Toyota Prius isn’t starting, but if it’s not fixed even after you have jump-started your car, then it clearly indicates that there is a problem with your ignition switch.

What Should You Do About It?

  • The first thing you can do to fix an ignition switch is to check your car’s spark plugs. These are at fault in most of the cases.
  • Also, ensure that you cross-verify the spark plugs in your Prius with the manual you are provided with. If the spark plugs are not of the required type, you must consult the professionals.
  • Take your car to the mechanic. Ask them to clean all the dirt and debris surrounding that area. Make sure that there is no contamination or traces of rust.

5: Major Security Issues

Every car manufacturer, be it a hybrid car or a normal car, is trying to update their safety and security protocols so that they can try to increase the safety test score.

This helps them in selling more units of their car. So, Toyota Prius is no exception to this.

The cars have different sensors and immobilizers that detect theft cases and ensure that the car does not start.

These sensors can sometimes malfunction, giving signals of theft to the car’s computer even though that is not the case.

In this case, the steering wheel gets locked, and the entire car system stops working.

However, like other issues, this issue is not as serious as others. It can be fixed within a few hours if you call a mechanic or even an electrician specializing in cars.

What Should You Do About It?

  • Make sure you keep your key fob near you. If you displace the one you have, you need to be concerned about the safety of your car.
  • The door cylinder of your Prius needs to be paid attention to. Ensure it is not malfunctioning and sending off fake alarms and signals to the computer.

Frequently Asked Questions

Q1. Why Won’t My Toyota Prius Start With New Battery?

Did you know that when you go out in the market to buy a new battery, it is often already half dead?

There is no way that someone with little knowledge about car batteries can find that out. Make sure to get it charged properly before installation.

Moreover, some batteries are already damaged, but the sellers try to sell them to get the defective piece off the shelf profitably. Try not to fall into this trap.

Q2. Why Won’t My Toyota Prius Start Even With A Jump?

If this is the first time you are giving a jump start to your Toyota Prius, you need to ensure that the cables’ polarity is not compromised.

Be careful in this case, and do not do it more than 2-3 times. If it does not work, the battery will not be blamed for the Toyota Prius not starting.

Q3. Why Won’t My Toyota Prius Start But Lights Work?

You might often experience this issue with a Toyota Prius. This might be because your car accessories are getting the right amount of electrical supply.

Your engine, however, is not getting the right amount of charge due to a faulty alternator or low battery. The starter motor might not be in good condition either.

Q4. Why Won’t My Toyota Prius Start But Cranks?

In the case of a Toyota Prius cranking, the main cause could be that the placement of your camshaft sensor has been tampered with.

Moreover, it tells you that the problem lies with your car’s engine, and you do not have to check the alternator or starter motor for this to be fixed.

Q5. Why Won’t My Toyota Prius Start Just Clicks?

The leading cause behind the clicking sound of your Toyota Prius is a faulty or damaged alternator. The alternator is not producing the right amount of charge for your battery.

It is either too high or too low. If it is too low, a drained battery would also become a cause of concern for you.

Q6. Why Won’t My Toyota Prius Start In The Cold Weather?

In the case of hybrids, the car would not start if the battery gets cold.

In this case, if your Toyota Prius is not working in cold weather, it might be because the battery’s temperature is lower than 22 degrees Fahrenheit.

Your combustion process and all the other important processes will be impaired due to this.

Q7. Why Won’t My Toyota Prius Start After I Get Gas?

In the case of hybrids, the gas or petrol you use must align with its internal structure. You cannot integrate low-quality gas or petrol with your Toyota Prius.

Moreover, you also need to see if there are any leakages, as the gas you get for your hybrid might leak out of the fuel pipelines.

Q8. Why Won’t My Toyota Prius Start But Radio Works?

Usually, when your car’s accessories, such as the radio, are working, the main issue revolves around the ignition switch or coil of your Toyota Prius.

You can try to use a duplicate key or clean the ignition switch to fix this problem.

Related: What Are The Worst Years For The Toyota Prius?


You cannot deal with hybrid cars as you deal with normal cars. The issues are quite different and require your utmost attention.

Toyota Prius is a great car, but that does not mean it would not malfunction. However, every issue it shows up with can be counter-attacked with a solution.

In my opinion, I have covered everything that you needed to know about why won’t my Toyota Prius start?

If one solution is not fixing your car, you can move forward to another solution or a different problem altogether.

Once you fix your car, take it back on the road and enjoy a trip with minimal fuel requirements.