How many catalytic converters are in a Toyota 4runner: Complete Guide

The catalytic converter converts detrimental gases into less harmful substances. The number of catalytic convertors varies from model to model and year too. But people want to know how many catalytic converters are in the Toyota 4runner.

Toyota 4runner uses two main types of catalytic converters. One is a three-way catalytic convertor and the other is an oxidation catalytic convertor. Both have various contributions to the effective working of vehicle engine systems.

The number of catalytic converters hinges on the model and manufacturing year but recent models have 2 catalytic converters to reduce the harmful emission of radiation. 

Types of catalytic convertors in Toyota 4runner

Types of catalytic convertors in Toyota 4runner
source: toyota-4runner

Toyota 4runner uses two types of catalytic converters. Their main purpose is to transform hazardous gases into less harmful substances that are not only environment friendly but they also keep the vehicle safe for a long time. Two convertors also provide a degree of redundancy, if one convertor fails to work other keeps working and continues emission without any hindrance. 

Three-way catalytic converter

A three-way catalytic converter (TWC) is considered the best convertor since it targets the three main and harmful pollutants i.e. carbon monoxide (CO), unburned hydrocarbons(HC), and nitrogen oxides (NOx). the chemical reaction starts in the convertor when it utilizes palladium, rhodium, and platinum and converts these detrimental pollutants to water, nitrogen, and carbon dioxide which are known as less harmful substances. 

Oxidation catalytic convertor (OCC)

Oxidation catalytic converter is designed to reduce unburned hydrocarbons and carbon monoxide. They react with metals palladium, rhodium, and platinum and convert them into carbon dioxide(C02) and water (H2O). 

What’s in catalytic convertors

What’s in catalytic convertors

A catalytic converter is considered a major component of the engine exhaust system because decreases harmful emission of gases into the atmosphere. It comprises invaluable metals like Platinum, palladium, and rhodium are valuable metals which make catalysts that speed up the chemical reaction. 

Want to know the best part?

It is made of ceramic since it can endure high temperatures and ensures a smooth chemical reaction inside the catalytic converter. 

Does catalytic conversion affect the function of the vehicle?

A catalytic converter is designed to stop the emission of harmful substances from the vehicle but any problem with this convertor can lead to malfunctioning of the vehicle. 


catalytic conversion produces heat and the convertor dissipates it but if it is not functioning properly then all heat accumulates inside the exhaust system that eventually overheates or even damages the components. 

Emission test failure:

A catalytic convertor needs to undergo a test for its compliance with environmental regulations. However, any problem in this converter can lead to failure in the emission test and can ban the vehicle from operating. 

Weird noises:

A faulty catalytic convertor starts producing loud and strange voices that are sometimes unbearable and can even affect the sense of hearing. Such sounds indicate the internal damage in the converter. 

Environmental damage:

A catalytic converter reduces the emission of harmful gases into the environment but if it cannot perform its duty then it leads to increased environmental pollution.

Increased fuel consumption:

A defective catalytic converter makes the engine work harder and it results in decreased fuel efficiency and increased fuel consumption. 

How much does the Toyota 4runner catalytic convertor cost 

How much does the Toyota 4runner catalytic convertor cost 
source: catconverterprotection

Toyota 4 Runner keeps changing its models and different years have different generations and these different model years have different types and designs of catalytic converters that affect their cost

Usually, a catalytic convertor’s average cost is around 2,200$ if you are buying brand new otherwise for used or old convertor prices may slightly differ. 

Likewise, OEM (original equipment manufacturer) are much more expensive than aftermarket converters and people can easily afford them.  

What are the most common issues with catalytic converters?

Catalytic converter plays a crucial role in environmental safety since they reduce the release of detrimental gases but sometimes they experiences some problems that include overheating, blocking, clogging, and oxygen sensor malfunction leading to decreased lifespan, contamination, rust, and corrosion due to harsh weather, excessive oil consumption because of faulty engine, catalyst coating or substrate. 

If you find any problem with the convertor then immediately consult the manufacturer or an experienced mechanic who can fix the issue urgently since such problems can permanently damage the catalytic converter.

How long catalytic converter need to be replaced

How long catalytic converter need to be replaced

A good quality catalytic convertor can last from 70000 miles to 100,000 miles but there are so many factors that decide the need for replacement. 

  • High-quality oil increases the lifespan of the convertor but using low-quality oil affects it badly 
  • High temperature, humidity, and corrosive substances decrease the longevity of catalytic converter
  • A properly maintained engine ensures the increased efficiency of the converter and extends its life as well. 
  • Constant idling and off-road driving cause wear and tear on the catalytic convertor that in turn decreases its life.


What is the function of a catalytic converter?

A catalytic converter decreases harmful emissions of gases by converting them into less harmful substances.

Can a catalytic convertor be cleaned or washed?

No, it is not advisable to wash or clean the converter. It is better to replace it as soon as you see any sign of damage or wear and tear,

Is there any benefit of having two catalytic converters?

Yes, dual catalytic converters can increase the efficiency of the system. The major benefit is if one stops working then the other keeps converting gases without any break. 


In short, the Toyota 4runner uses two types of catalytic converters and they both work collectively to stop the emission of dangerous substances in the environment and are highly effective in increasing the performance and longevity of the vehicle. If one stops working for any reason then another can be used as a s backup.