2018 Toyota Sienna Problems and Top Complaints – Is Your Car A Lemon?

Power sliding door, engine and powertrain issues among the top complaints received by the NHTSA from vehicle owners

Updated on Author: Brian Jones

Updated on Author: Brian Jones

Minivans might not be as popular as they once were, but the 2018 Toyota Sienna seems to still have a following. The newest lineup is labeled as “life meets style,” but good looks might be all this model has to offer. Owners are dealing with trouble related to the engine, powertrain, structure and vehicle speed control.

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NHTSA Complaints for the 2018 Toyota Sienna

Complaint CategoryNumber of Complaints
Unknown Or Other
Power Train
Fuel/propulsion System
Vehicle Speed Control
Electrical System
Fuel System, Gasoline
Air Bags

Problems with the Engine

When it comes to powering a vehicle, the engine is essential for all operations. When the motor isn’t reliable, all bets are off.

That’s what is shown with this NHTSA complaint. “The contact owns a 2018 Toyota Sienna. While driving at low speeds making a right turn the oil warning indicator light illuminated and contact noticed the oil was low. The vehicle was taken to [dealer] where it was diagnosed that the oil was low and additional oil needed to be added. The vehicle was repaired however, the failure recurred. The manufacturer was contacted but no further assistance was provided. The failure mileage was 3,700.”

There’s no reason for a new vehicle to go through so much oil. While there has been no explanation for it, there is a recall that can lead to other engine troubles, particularly stalling. NHTSA Campaign number 20V012000 states that the low-pressure fuel pump inside almost 700,000 vehicles can go bad, causing the vehicle to stall. When this happens, owners are left stranded in the middle of the road, with a car full of kiddos to protect. At least the van looks good sitting on the roadway. It’s a good thing Toyota spent so much time perfecting the style. Owners might have preferred an uglier van that doesn’t stop while driving.

Problems with the Transmission

In conjunction with the engine, the powertrain is vital to the everyday operation. Yet, this is another essential component that fails on the Sienna.

One Edmunds review states, “Tranny not very smooth – have to literally be at complete stop before moving again or get some unsmooth tranny issues as it tries to figure out what to do.”

Toyota hasn’t hidden any transmission-related problems. One of the communications, Service Bulletin #T-TT-0580-19 states that some of the models have a leaking Transmission Side Cover. For now, the automaker is investigating the case and the fix. Whether it’s leaking transmission fluid or burning through oil, this Sienna proves it doesn’t know how to hold onto its fluids. That must not be part of the style that was designed.

Problems with the Power Sliding Door

The Toyota Sienna isn’t the lowest-priced minivan on the market. It should be constructed with high-quality materials and well-built to last, but that’s not the case either.

Another Edmunds users says, “Both side view mirrors click / jostle when accelerating or decelerating. It is a really distracting and started within a year of owning a brand new car (on both mirrors). The customer care team told us this was normal and even tried to tell my wife it was an ‘auto adjust’ feature. (trust me, the loud ‘adjustment’ is not normal and happens at random times when accelerating or braking). I took the issue to their management team thinking there is no way a company would try to justify that loose mirror housings on a car are normal but sure enough … they doubled down. It’s really mind blowing.”

The side mirrors aren’t the only parts to worry about. Service Bulletin #ZH5_Dealer Lette states that Sienna owners are struggling with the power sliding door. It turns out that corrosion has left the sensor inoperable. Either the power closing door doesn’t close at all, or it starts to and then reverses. Getting into the Sienna is like playing a game, but the sliding door seems to be winning.

Problems with the Vehicle Speed Control

On modern vehicles, there are speed control systems set up to regulate how fast it travels. When these systems malfunction, occupants are left at risk of an accident.

An NHTSA comment illustrates the point, “I was turning left on a country road at 25 mph. The car decelerated and a yellow warning came on. The dealer said the car though it was going to roll over. They did the software update. The car still decelerated. Yellow light comes on most of the time when starting up.”

Toyota hasn’t issued any communication about this problem. Of course, it makes no sense that this dealer would assume that the van thought it was going to roll at 25 mph. If that’s the case, then drivers better take it really easy when going around turns. While Toyota was creating the style, they must not have factored in the dynamics that are required to turn. Either way, this minivan is a lemon and definitely not meant for much else than to look at.

Your Lemon Law Legal Rights

Think you have a lemon? Sit back and let the experts work out your lemon case at no cost to you. The law makes Toyota pay legal fees. You may be able to get your lemon out of your life. Every year, auto manufacturers buy back, replace or pay cash settlements to thousands of ‘lemon’ owners like you.

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Brian Jones

About the Author:

Brian Jones spent more than 30 years working as an ASE Certified Master Tech and Parts Specialist at multiple dealerships. Brian has become an authority in the industry, traveling across the country to consult for car dealerships and contributing his expertise as a writer for several major automotive publications. In his spare time, Brian enjoys working on pickup trucks, muscle cars, Jeeps and anything related to motorsports.

See more posts from Brian Jones

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