5 Most-Common Problems With Toyota Sienna (Explained)

The Toyota Sienna is a popular minivan that combines durability, longevity, reliability, and value for money.

To top it all, the Sienna has a great fuel economy. However, what are the problems we should expect from our favorite minivan.

While the average annual repair cost for a Sienna is only $554, it has problems that are common among models. We discuss those problems in this article.

1. Problem With Electric Sliding Doors

The sliding doors issue is one of the most commonly reported problem. Many drivers complained of a partial failure. This means they could open the doors manually, but the buttons stopped working.

For other drivers, there could be total failure.

Possible Causes and Solutions

Here’s the major reason the electric sliding doors develop problems. The cable system usually gets worn out and damages the latch motor behind the door’s mechanism.

More often, one door usually malfunctions before the other. Sometimes, the doors stopped functioning optimally after major repairs. its possible technicians tampered with the connection while conducting repairs.

Another reason the doors may malfunction could be due to circuit overload. An overloaded circuit can upset the fuse. This can prevent normal door operations.

Often, replacing only the affected parts can get the problem fixed, saving you a lot of money than if you were to fix the entire door.

Sliding door problems are common in different years, spanning 18 model years. That shows that the doors are a common problem with the Sienna.

You may need to replace your door latch or latch motor.

Most times, you can manually get your doors open manually if they don’t open up automatically. While this is only a temporary solution, it can get you out of pretty tight situations.

One precaution is to not get too comfortable operating your doors manually when they stop working by pressing the button. This is because if a problem affects the doors only partially, it is bound to spread out gradually.

Therefore, fix any problems as soon as they occur.

Also, when a cable gets worn out, it has to be replaced. Replacing the cables, if done by seasoned hands, can make the doors function optimally as before.

Related: How Long Do Toyota Sienna Last? (Solved & Explained!)

2. Faulty Oxygen Sensor

Another common problem with the Sienna is the oxygen sensor. The oxygen sensor measures the ratio of oxygen to the exhaust gasses.

Based on complaints, problems with the oxygen sensor are common among 16 model years. If your Sienna has a bad oxygen sensor, it affects the engine in diverse ways.

It may affect the daily operations of your engine. This includes operations involving combustion and acceleration. The oxygen sensor also helps the car’s computer to know when to regulate the air-fuel mixture and adjust its proportions.

When the oxygen sensor fails, it affects the operations of the catalytic converter. Therefore, the oxygen sensor should be functional at all times. This is because it alerts the driver to know when to inspect the catalytic converter.

Possible Causes and Solutions

Several things can damage the oxygen sensor. Contamination from an oil-rich mixture and burning of the engine coolant in the combustion chamber can cause the sensor to fail. Age, corrosion, and electrical issues can also make the O2 sensor to stop working.

A problem with the oxygen sensor causes a disruption of the normal combustion process. This is because the control system automatically adjusts the air-fuel mixture during injection processes to maintain best conditions for combustion.

The catalytic converter aims to reduce the pollution to the atmosphere. This happens when it causes counter reactions to combat the excess toxins produced because of combustion. It can only do this when the oxygen sensor functions correctly.

When the sensor fails and the converter can’t work properly, the car may violate laws by exceeding the pollution limits.

For many Sienna owners, the “check engine” light is a common sight. It comes on when there’s a problem with your emission control system.

The number one precaution should always be to inspect your emission system once the light comes on. The oxygen sensors and catalytic converter are components of your car’s emission control system.

You might notice that more fuel is being consumed by your car. When the fuel economy is poor, it may be a red flag.

Your oxygen sensor might be bad. This means it won’t detect the excess fuel present in the air-fuel mixture in the combustion cylinders.

If you don’t get it fixed, you would have to spend more money on fuel. Not to talk about the pollution that would occur because of an idle catalytic converter.

You can notice another red flag on your engine performance. A bad oxygen sensor would affect the overall performance of your engine.

If you notice reduced response from your engine when you speed up, check your oxygen sensors and replace them if they are bad.

3. Oil Leaks and Oil Pressure Loss

This is another common problem with the Sienna. It mostly occurs because of a perforated oil line.

They found the line to be so defective that Toyota provided an improved line. This did little to solve the problem, as the oil lines didn’t cease rupturing.

Drivers complained of oil lines leaking while they drove. Others complained that the warning lights never came on. This is dangerous because having no warning lights wouldn’t alert the driver that there’s an oil leak.

Possible Causes and Solutions

A defect in the engine oil hoses is the primary cause of this problem. Rodents can also damage the oil lines.

In case of a perforated oil line, replace it and clean up all the spilled oil.

To be on the safe side, inspect your oil line randomly at intervals, especially if the oil light fails.

You can add extra protection against rodents by running your car regularly and parking inside a garage. Do not keep food or anything that might attract rodents to your car.

Related: Toyota Sienna In Snow & Winter Driving? (Explained)

4. Cracks on the Dashboard

While this may seem like a less threatening problem when compared to others, it is common among Siennas.

Many drivers complained about cracks on their dashboards before their cars even reached 100,000 miles. This problem, however, seems to only affect older models.

Siennas manufactured after 2010 have few or no reported cases of dashboard cracks. Toyota seems to have found a solution to the problem in recent years.

You should, however, look out for older models from 1998 to 2010. Those are the years mostly affected by dashboard cracks. The 2004, 2005 and 2006 models also seem to be notoriously famous for dashboard cracks.

Some drivers complained their dashboards appeared to be melting. Others expressed their fears over how the cracks could affect airbag deployment in emergencies. Sometimes, the cracks caused the car radio to malfunction.

Car Complaints gave the 2004 Sienna a 7.8 severity rating for dashboard cracks. The 2005 and 2006 Siennas have 6.9 and 7.0 severity ratings, respectively.

Possible Causes and Solutions

The primary reason for the cracks in old model Siennas is prolonged exposure to the sun’s ultraviolet rays.

You can protect your car from heat by parking in garages or using car covers regularly. Another strategy is to use windshield shades to protect your dashboard from ultraviolet rays.

Since dashboards also crack because of dryness, you can apply moisturizers that have gone through several tests and have great reviews. You should also avoid using damp rags to clean your dashboard.

Many drivers suggested Toyota should recall the affected vehicles. Toyota, however, seemed to do little at the time as many drivers got replies that said their “warranty periods had expired”.

A lot of drivers with affected Siennas had to get their dashboards replaced, while others attempted repairs. The repair costs ranged from $900 to $1,500.

Another option one could go for is an aftermarket dash cover. This may reduce or even prevent cracks from appearing on the dashboard. However, for the affected Toyota Sienna model years, the cracks seem to be inevitable in most cases.

5. Sudden Loss of Power After Deceleration

This is the worst complaint about the Sienna recorded by Car Complaints.

Drivers complain that their car engines lose power whenever they slow down. This happens whether it is to take a turn or to get over a speed bump.

In most cases, the car takes some time (usually a few seconds) before the engine picks up and speeds up. It also speeds up with a jerking action before it picks up fully.

Another problem with the loss of power is that it directly affects the transmission. This is because the transmission usually has to go through large sudden shifts to cope with the speed change.

When this happens constantly, you’re at risk of reducing the service life of your transmission.

Based on reports from drivers, it may also be more common in colder regions. Drivers also complained that after many dealerships scanned the car for problems, they usually detected nothing.

The danger with the engine losing power abruptly is that it increases the possibility of an accident happening. If the power loss occurs on a busy highway, incoming cars from behind would likely collide with the slowly speeding Sienna.

Possible Causes and Solutions

Several factors can cause this problem, from faulty plugs, bad fuel pump or fuel filter, damaged engine cylinder, defective O2 sensors, and contaminated transmission fluid, among others.

There are ways to prevent engine power loss in your Sienna.

  • Change Engine and Tranny Fluids: The first precaution involves changing your engine and tranny fluids more frequently during extremely cold weathers. Since the cold increases the viscosity of the liquid, it reduces performance and can make your car jerk up when you speed up.
  • Inspect Fuel Pump: If the fuel pump develops a fault, it affects the rate at which fuel would be transported to the engine. This can cause car jerking.
  • Inspect Fuel Filter: A faulty fuel filter would allow impurities (usually tiny particles) to get to the engine. These particles can obstruct the normal combustion process and cause your engine to jerk. If dirt fills the fuel filter, it might also reduce the amount of fuel that gets to the engine. Whatever the case, it can have a great impact on your engine.
  • Faulty Cylinders: Eensure your cylinders are in great shape. This is more common in older vehicles with older engines.

Related: 11 Toyota Sienna Statistics You Should Know (Facts & Numbers)

General Pros and Cons

Here are some of the pros and cons of the Toyota Sienna:

Pros

  • Ample space
  • Exceptional infotainment features
  • Abundant cargo space
  • Myriad small item storage areas
  • Decent fuel economy
  • Impressive visibility
  • Respectable Climate Control performance

Cons

1. Problem With Electric Sliding Doors
2. Faulty Oxygen Sensor
3. Oil Leaks and Oil Pressure Loss
4. Cracks on the Dashboard
5. Sudden Loss of Power After Deceleration

What Do the Reviews Say?

“The Sienna bucks the minivan trend with an all-hybrid lineup, but it falls behind the segment leaders in both acceleration and practicality.”

Source: Car and Driver

Resale Value of Previous Model Years

The Toyota Sienna has quite a remarkable resale value. It retains its value pretty well, it’s also among the top ten minivans with the best resale values.

Model Year Mileage (Miles) Resale Value ($)
2011 120,000 8,205
2013 96,000 11,956
2014 84,000 13,342
2017 48,000 17,818
2019 24,000 29,493

The above information is based on a National average of 12,000 miles driven per year.

Resources

Toyota Sienna | repairpal.com

Toyota Sienna | carcomplaints.com

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