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What is a catalytic Converter

Components of Catalytic Converters

Inside the Catalytic Converter

The catalytic converter is designed to convert harmful emissions, produced by an internal combustion engine, to less-harmful elements: H2O (water), CO2 (carbon dioxide) and N2 (nitrogen).  To perform this conversion, the catalytic converter works with a vehicle's PCM (Powertrain Control Module) and other emissions control devices.  
OBD II (On-Board Diagnostics Version 2) monitors the emissions control devices and provides feedback on their operating conditions.  
As the EPA (Environmental Protection Agency) updates emissions standards, the OBDII system becomes more sensitive to fluctuations in emissions performance. 

Components That Make Up Catalytic Converters:  

1. Stainless Steel Body 

For long life and durability. The ribbed body minimizes expansion and distortion, as well as forming channels that protect the cushioning mat from direct exposure to exhaust gases.

2. Monolithic Free-Flowing Substrate 

The substrates are the backbone of the converter. This is where the proprietary mix of precious metal(s) and the washcoat formulated to store O2 allow the conversion process to take place. Converters are available in single- or multiple-substrate designs.

3. Catalyst Cushioning Mat 

The mat cushions the converter substrate, holding the ceramic catalyst in proper alignment. It creates a seal between the substrate and body, making sure all exhaust goes through the catalyst; and also allows for thermal expansion of the body.

4. Body and Pipe Heat Shields to Match OE 

Deflects heat created by the converter away from the vehicle's undercarriage.

5. O2 (Oxygen) Sensors

Another vital part of an emissions control system, these sensors are placed before and after the catalytic converter on an OBDII vehicle. They are designed to monitor the O2 storage efficiency of the converter. This information also allows the PCM to adjust fuel controls.


The content contained in this article is for informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.

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