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7 Common Problems Of A Toyota Prius Prime

7 Common Problems Of A Toyota Prius Prime

What kind of problems does a Toyota Prius Prime usually have? In this blog, we’ve outlined the most important things you should watch out for when you’re in the market for a Prius Prime. However, let’s first start with a quick answer.

The most critical problems of the Toyota Prius Prime are the Hybrid system shut down in the 2017 model and the loss of stability control and brake assist in the 2019 and 2020 models. The 2017 model also has rollaway and short circuit risks. Other problems include the low-strength windshield for the earlier models and the ECU software problem in the 2022 model. 

That was the most straightforward answer possible. In the article below, we’ll discuss every problem in detail. This includes identifying it, fixing it, and determining how much it costs to fix. Read on!

1.  Hybrid System Shutdown (Inverter Failure)

In some Prius models, an issue with the hybrid system forces it to shut down, resulting in vehicle stalling. Only the 2017 model of the Prius Prime is affected by this problem. The root of the problem is the faulty Intelligent Power Module (IPM) inside the inverter of the vehicle, an excessive voltage in the IPM can cause the inverter to fail and the hybrid system to shut down.

Toyota issued a recall to fix the problem in June 2020. The dealership will adopt one of two approaches to fix the problem. A software update is sufficient to rectify the problem if no damage has been incurred and the inverter is operational. However, if the inverter has failed, the inverter assembly will need to be repaired or replaced before updating the software. Of course, since it’s a recall, all repairs will be done free of charge.

If you’re interested in getting a 2017 Prius Prime, we would urge you to investigate if the vehicle was a part of the recall and if the fix was implemented since the recall is relatively new and performing the repairs yourself will cost you around $2000 for a new inverter and $650 or more for a refurbished one.

2. Rollaway Risk

There has been a rollaway risk associated with the 2017 Prius Prime. It was complained by some consumers that the vehicle could roll away if it was left in any gear other than park while the ignition was on. Rollaway vehicles endanger people close to them and cause severe property damage.

This rollaway risk is caused by a faulty parking brake cable that unfortunately disengages from the mechanism. Toyota’s recall for this issue fixes it by installing a clip at the parking cable end to prevent it from disengaging. This is done at the dealership, free of cost.

3. Engine Wire Harness Problem

A wire harness problem in the 2017 and 2018 Prius Prime could result in an electrical short that increases the risk of a fire. The connection between the engine wire harness and hybrid power control unit could contact the cover, causing wear that could lead to an electrical short circuit. 

Toyota issued a recall to solve this problem. The dealers will inspect the engine wire harness assembly and replace it if any damage is found, free of charge. Once the damage is dealt with, the dealers will add a protective tape or sleeve to prevent future damage to the assembly, also free of charge.

The cost of replacing the engine wire harness on your own ranges from $1,000 to $1,700, so it’s best to check if the harness has a protective coating installed when buying a used 2018 Prius Prime. 

4. Loss Of Stability Control and Brake Assist

The 2019 and 2020 Prius Primes were included in Toyota’s recall to fix the loss of stability control and brake assist. The recall is limited to 2019 and 2020 model years but spans multiple Lexus and Toyota models, so it’s something to watch when looking to buy used cars from these manufacturers.

Stability control is vital to prevent the vehicle from skidding, while brake assist helps fully activate the brakes in an emergency. Therefore, the failure of either one of these systems significantly increases the risk of severe crashes and injuries.

The loss of stability control and brake assist can be traced back to a failing brake booster pump. There may be a malformed part within the booster pump that causes an electrical connection failure resulting in multiple dash lights illuminating.

If you’re in the market for a 2019 or 2020 Prius Prime, it’s best to check if the brake booster pump has been replaced. Toyota had a recall for this issue, and dealers would inspect and replace the brake booster pump free of charge if required. Replacing the brake booster pump on your own would cost you anywhere from $300 to $1250, so it’s best to ensure the problem has already been resolved.

5. ECU Software Problem

A loss of driver power was an issue faced by owners of the 2022 Prius Prime. Although it’s alarming for this problem to occur in such a new vehicle, the problem was traced back to a simple software issue. The Engine Control Unit (ECU) software would incorrectly detect an error and shut down the hybrid system resulting in a loss of driver power.

The fix was just as simple. Toyota’s recall required the vehicle to be taken to the dealership, where it would receive an ECU software update rectifying the issue.

The recall is relatively new, so it’s recommended to check if your vehicle is a part of the recall and to get the problem sorted out if it is.

6. Windshield Problems

The somewhat easy cracking and shattering of windshields has been a problem for Prius Prime and Prius owners alike in the 2016 to 2018 models, 2017 – 2018 for the Prius Prime. After going through multiple forums and sites and researching the lawsuit concerning this issue, we have come to the following conclusion. The windshield problem is here to stay.

The windshields used on these models are unique as they are lightweight and improve the vehicle’s efficiency. Nevertheless, this does make them more susceptible to cracks, and they can shatter more quickly than the older and stronger windshields we are accustomed to. There is no evidence that the windshields are defective, just that they are unique and, unfortunately, weaker in strength.

If you’re in the market for a Prius Prime, it’s best to keep in mind that this is something that you’ll have to live with. Most consumers favor repairing the cracks rather than replacing the windshields since the windshields can cost anywhere between $500 and $1100, whereas repairs tend to cost between $100 and $200.

It’s not a problem that occurs too often; it’s just one that’s heavy on the wallet if and when it does. However, we have seen this issue in other Toyota vehicles including the RAV4 Hybrid.

7. Soy-Coated Wiring

Soy-Coated wiring has become a common issue for most brands, including Toyota. Most automakers switched to soy-based coating for their wiring because it was more biodegradable and so more eco-friendly. Although it’s better for the environment, it’s also better for the automaker as these soy-based coatings are cheaper than their plastic counterparts.

The problem with these soy-based coatings is that they attract rodents which then like to chew on them and use them as nesting material. This could cause an array of problems, any system that utilizes wires accessible to these rodents is at risk of failing. This has become quite the problem since there is no easy solution, and it’s a problem found in most vehicles by most automakers.

There are some simple steps to include into your routine to try and catch these rodents before they cause an expensive problem. This includes regularly opening the hood and looking for signs of rodent activity, looking for shredded pieces of wire where you park your cars and cleaning out all the food in your car.

What’s The Worst Year Of The Toyota Prius Prime?

Toyota Prius Primes are reliable cars that should last you around 200,000 miles to 250,000 miles. Some consumers have reported exceeding the 300,000 miles mark on their Prius, so the Prius Prime should be able to give you similar results. The Prius Prime first came out in 2017; We’d like to look at which of these model years are its finest and which are best avoided.

We would have to say the worst models of the Prius Prime are 2017 and 2020. These models were the most complained about by users on sites such as and had a relatively higher number of complaints on the NHTSA site as well. The main problems of the 2017 Prius Prime were hybrid system shutdown, short circuit risk due to the wire harness wear, and the rollaway risk due to the disengaging parking brake cable. These issues were all dealt with, with recalls from Toyota. Some problems, such as the low-strength windshields, weren’t dealt with.

The most critical problem of the 2020 model was the loss of stability control and brake assist, which increased the risk of severe crashes and injuries due to reduced control over the vehicle and its braking system.

All other models of the Prius Prime are excellent options, but we would have to select the 2021 model as our top pick. The 2021 model of the Prius Prime has the least amount of complaints, and it also doesn’t share the major issues and recalls of the other models. That means fewer troubling trips to the dealership for recall information and fixes!

Closing Thoughts

The Toyota Prius Prime is generally a reliable vehicle, but it does have several issues to be aware of. Key problems range from the Hybrid system shutdown in the 2017 model to stability control and brake assist losses in the 2019 and 2020 models.

The 2017 model has also faced rollaway and short circuit risks, while the 2022 model experienced an ECU software problem. Earlier models had issues with windshields of low strength.

Having an in-depth understanding of these problems can inform your decision when considering a Prius Prime and ensure that you are prepared for potential issues that may arise. Just as you need to know the type of fuel to use in your Prius you should also know what to expect when it comes to common problems.

Always consider these factors along with the costs associated with identifying and fixing such problems. It’s advisable to consult with automotive professionals or your dealership to ensure you’re making the best decision based on your specific needs and circumstances.


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