Does a Toyota Sienna have a catalytic converter?

Yes. All modern Toyota Sienna models have catalytic converters as part of the exhaust system to meet emissions standards.

Over the years, the Sienna has evolved from its gasoline-powered origins to the current hybrid-only generation (2021–present). While the exact number and placement of catalytic converters can vary by model year and market, the purpose remains the same: to reduce pollutants such as carbon monoxide, hydrocarbons, and nitrogen oxides before the exhaust leaves the vehicle.

What a catalytic converter does

A catalytic converter is a key component of a vehicle’s exhaust aftertreatment system. It uses precious metals and catalysts to transform toxic gases (CO, HC, NOx) into less harmful substances (CO2, H2O, N2). This process helps vehicles meet emissions regulations and improves overall air quality.

Catalytic converters in the Toyota Sienna

In the Sienna, as in most modern gasoline-powered vehicles, the catalytic converter is standard equipment. In many Toyota hybrids, including the Sienna, the exhaust system is designed with multiple catalytic converters to ensure efficient emissions control across a wide range of operating conditions. The exact configuration—how many converters and where they are located—depends on the model year, engine family, and regional emissions requirements.

Current generation (2021–present)

The 2021+ Toyota Sienna is hybrid-only and relies on a contemporary exhaust aftertreatment setup to meet stringent emissions standards. The catalytic converter(s) are integrated into this system, with placement and count tailored to the hybrid drivetrain. For precise details on a specific vehicle, consult the owner’s manual or a Toyota service bulletin for that year and market.

Older generations

Earlier Sienna generations also included catalytic converters as required by the emissions standards of their times. While the general concept remains the same, the number, placement, and specifications of the converters varied by generation and market. Always refer to the service documentation for exact information on a given vehicle.

Here are essential facts about catalytic converters in the Sienna:

• They reduce pollutants such as CO, hydrocarbons, and NOx, helping the vehicle meet emission standards.


• The typical Sienna layout includes a catalytic converter in the exhaust path, with the possibility of multiple converters in hybrid models.


• Locations are generally along the underbody exhaust line, often with heat shielding and protective casings.


• Maintenance and failures can occur from overheating, physical damage, or contamination; common warning signs include reduced performance and a check engine light.


• High replacement costs and theft risk are considerations, due to the precious metals used in the catalysts.

Concluding from these points, the catalytic converter is a standard and essential component across Sienna generations. For exact specifications on a specific year and market, check the owner’s manual or contact a Toyota dealership.

Maintenance and issues to watch for

Signs of a failing catalytic converter include a glowing check engine light, reduced acceleration or power, poor fuel economy, and sometimes a rotten egg-like odor from the exhaust. Diagnostic codes such as P0420 or P0430 often indicate catalyst efficiency problems. If you suspect an issue, have a certified technician diagnose and, if needed, replace the converter with OEM-compatible parts to maintain emissions compliance.

Summary

In short, yes—the Toyota Sienna has a catalytic converter as part of its exhaust system across its generations. The current hybrid-only generation continues to use catalytic converters to meet emissions standards, with configuration that can vary by model year and market. For exact details on a particular vehicle, refer to the owner’s manual or consult a Toyota service professional.

How many catalytic converters does a Toyota Sienna have?

A Toyota Sienna has three catalytic converters on most models, which includes one for each exhaust bank and a third downstream converter. The exact number can vary by year, with some older models potentially having a different setup, so it is best to confirm with a mechanic or check your vehicle's specific parts diagram. 

• Multiple converters: Most Toyota Sienna models, like the 2004 and 2006, have three catalytic converters. These are typically two "warm-up" or manifold converters, one for each engine bank, and a third main converter further downstream. 
• How to confirm: To be certain about your specific model, you can visually inspect the exhaust system under your vehicle or consult a parts list for your year. A mechanic can also confirm the number of converters on your Sienna. 

What Toyota models are catalytic converter theft?

The newest models of Toyota Prius don't contain as many precious metals as the older versions and are less likely to be impacted by theft. That said, Toyota Prius models from 2004 to 2009 are much more likely to be targeted by thieves due to the high concentration of precious metals in their catalytic converters.

What is the common problem with Toyota Sienna?

Common Toyota Sienna problems include issues with the sliding doors, cracking dashboards, and problems with the exhaust system. Older models are known for transmission failures, while the 2021 hybrid version has had specific issues with its 12V battery and a toe sensor for the sliding door. Depending on the model year, other reported problems include oil leaks and various issues with oxygen sensors.
 
This video discusses some top complaints about the 2025 Toyota Sienna, including issues with the second-row seats and hands-free sliding door: 1mPoodle DadYouTube · Jan 20, 2025
Common problems by category 
This video highlights common problems with the sliding doors in the 2011-2020 Toyota Sienna models: 56s1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · Jul 17, 2024

• Doors: Electric sliding doors frequently malfunction due to faulty motors or cables, with the toe sensor on some models being inconsistent. The rear hatch can also get stuck. 
• Dashboard: Cracking dashboards are a recurring issue for many model years. 
• Transmission: Some older model years, particularly the 2004 and 2017 models, have reported significant transmission issues. 
• Engine: Problems like oil leaks from the front cover, faulty oxygen sensors, and check engine lights due to EVAP systems are noted. The 2005 model has been specifically linked to head gasket failures with coolant leaks and overheating. 
• Electronics: For hybrid models like the 2021, a common complaint is that the 12V starter battery is undersized and dies frequently. Some users have also reported issues with Android Auto connectivity and the wireless charging pad. 
• Exhaust: Issues with the muffler, catalytic converter, heat shields, and exhaust manifold, as well as leaks, have been reported. 

This video explains some common issues with the 2011-2016 Toyota Sienna, including head gasket leaks: 57sThe Car Care NutYouTube · Aug 11, 2020
Before you buy

• Check for leaks: Inspect for signs of oil and coolant leaks. 
• Test the doors: Make sure both sliding doors and the rear hatch open and close smoothly. 
• Inspect the dashboard: Look for any signs of cracking. 
• Verify transmission history: For specific models like the 2004 and 2017, pay extra attention to transmission performance. 
• Confirm a history of maintenance: Proper maintenance, especially regular oil changes, can help prevent certain engine issues like sludge buildup. 

How much is a catalytic converter for a Toyota Sienna?

between $1,915 and $2,090
The average cost for a Toyota Sienna Catalytic Converter Replacement is between $1,915 and $2,090. Labor costs are estimated between $377 and $553 while parts are typically priced around $1,538.