April 14, 2020

Toyota Prius Problems

Common 2010-2015 Toyota Prius Problems and Issues (And How To Fix Them)

The 2010-2015 Toyota Prius' problem include tricky brakes that need adjusting to, burning oil in high-mileage models, short-lived headlights fixed by a recall and potentially expensive replacement hybrid batteries. The Prius is an exceptionally reliable vehicle that has some simple issues that need to be addressed.

Leave it to Toyota to make my job writing about mechanical weaknesses in cars short and easy. While the name "Toyota" is synonymous with "reliability" in many circles, that doesn't mean even the almighty Prius doesn't have some common problems and issues.

The Bad And "Bad" Brakes

Owners have struggled with the Prius' braking system since day one. Most notably 2010 Prii (that is indeed the plural form for "Prius") were recalled due to nitrogen gas potentially leaking into the brake fluid from the brake booster pump assembly.

This would cause Prii to have weak braking ability, potentially causing an accident. Even if your Prius was taken in for this recall, owners still report problems braking in unideal surfaces. As a result, those same 2010 Prii were also recalled for a software update reworking the ABS, so that owners would be able to brake more effectively on slippery or loose surfaces.

However, even after the update many owners still report questionable braking performance on those tricky surfaces and even experience unintended acceleration. So many that the overwhelming majority of reports on the National Highway Traffic Safety Administration website are about "accelerating" forward when attempting to brake.

Prius Sudden Acceleration

Reading through forums and this Wikipedia article, what owners are actually experiencing are the regenerative braking features shutting off when traction control kicks in. Driving around town, the vast amount of braking done is exclusively covered by the regenerative braking as way to recharge the hybrid's battery, improving fuel economy. However, Toyota has the software shut off the regenerative braking when the traction control activates.

So imagine you are driving in the rain and brake over a slick manhole cover causing the car to slide a bit. When the traction control activates, the Prius shuts off the regenerative braking thus cutting any braking you were doing, giving you the illusion of accelerating while you are pressing on your brakes. That obviously seems like a bad design and may make you wonder "well are my brakes going to be worthless in bad weather?" not exactly.

The Prius' regenerative brakes are not the entire braking system, there are still standard disc brakes on a Prius. What most owners probably don't realize is that those disc brakes only kick in when the driver presses hard enough to activate over roughly 30 percent of the braking potential. So if you experience that "sudden acceleration," just brake hard enough to activate the disc brakes and the car will slow normally. Prius enthusiasts know about this issue and use this simple workaround if they experience that "sudden acceleration" so many concerned drivers are writing about on the NHTSA website. Most seem to agree it's a bad feature, but luckily is something that can be worked around.

Low Engine Oil Pressure

While void of any catastrophic failures like the engine or transmission falling apart, the Prius does have some nuisances that owners should be ready for.

The first is that the Prius likes to burn oil which often shows itself as a low oil-pressure light appearing. This issue seems to plague older, higher-mileage Prii. Luckily the community came together and found a solution to the problem... just add more oil! Some owners report swapping to a heavier oil slows the consumption, but otherwise it is not too bad of a problem.

Other annoyance Prius owners experience are their headlights burning out with startling frequency. The problem is apparently due to a bad wiring harness causing the bulbs to short early. Toyota announced a recall in 2017 for 2010-2012 Prii that would replace the wiring harness and any burned-out headlights affected by the under-performing wiring harness. Other Prius years don't have this problem.

Prius Battery Life

The elephant in the room regarding all hybrids is about replacing their big, expensive battery. The Prius has a warranty covering that battery for eight years, 100,000 miles or ten years, 150,000 miles in California. If your battery fails outside the warranty, replacing it could cost thousands of dollars. There are multiple services to cover some of the cost including swapping in a refurbished battery (that still comes with a warranty), reconditioning your own battery or swapping the battery yourself. Unfortunately there are too many factors determining how long a battery will last. Some owners report the original batteries failing at 60,000 miles, others go over 200,000 miles.

We wish we could offer you better advice in regards to the hybrid battery system, but it ultimately shouldn't affect your decision too much. The Prius is a reliable car and while the battery failing could be a costly fix, a less-reliable car constantly going in and out of the shop will likely cost you more over time.

The Toyota Prius' problems are limited and the car carries on Toyota's excellent reputation for reliability and if you are in the market for one, look at our used-car checklist for what to check out before you buy and our inventory. If you want to make sure a Prius is right for you, also look through our "What Car Should I Buy?" guide.

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Modified photo from PGE