CARB Compliant Catalytic Converter vs EPA or OEM

CARB Compliant Catalytic Converter Versus Federal or OEM Converter

When it comes to catalytic converters, there’s a lot of confusion about what’s legal, what’s durable, and what works best for your vehicle. When shopping, you’ll find several choices, such as a CARB compliant catalytic converter, Federal, or OEM converter. Let me break it down for you in plain terms, so you can make an informed decision.

Let’s explore the three main types: EPA (or Federal) Aftermarket, CARB-Compliant, and OEM converters.

Federal or EPA Aftermarket Catalytic Converters

EPA (or Federal) catalytic converters are designed for vehicles in states that adhere to federal emissions standards, which exclude California, New York, Colorado, and Maine. Aftermarket Federal/EPA converters are a budget-friendly option for most vehicles. They are Federally mandated to maintain emissions for 25,000 miles and have a five-year structural warranty.

Some brands, like AP Emissions, even go above and beyond, doubling the emissions warranty to 50,000 miles. This durability makes them a solid choice for most drivers outside CARB-regulated states.

CARB Compliant Catalytic Converters

CARB (California Air Resources Board) catalytic converters are the gold standard for emissions compliance. These converters are legal for use in California, Colorado, New York, and Maine, with stricter emissions regulations. CARB converters are independently tested to ensure they keep the check engine light off and meet the highest environmental standards.

CARB converters come with a five-year or 50,000-mile emissions and structural integrity warranty.

If you’re making a repair in California, Colorado, or New York, you must use a CARB-compliant aftermarket catalytic converter, regardless of whether the vehicle was originally certified for sale in California.

States requiring CARB-compliant catalytic converters have periodic emissions inspections that vehicles must pass. If you live in one of these states and install an EPA-compliant converter instead of a CARB-compliant one, your vehicle will fail the inspection. To meet the requirements, you’ll need to replace it with a proper CARB-compliant catalytic converter.

• CARB Converters Have More Precious Metals—  They contain higher amounts of platinum, palladium, and rhodium.
• CARB Converters are Designed For Greater Durability—  Designed to withstand harsher conditions and last longer.
• CARB converters Cost More— All that quality comes with a heftier price tag.

How to Identify a CARB Compliant Catalytic Converter

All CARB compliant catalytic converters must include an embossed steel label indicating the California Executive Order Number, the part number and the manufacture date. In addition, look for markings or stickers that state “CARB Compliant” or similar language, often in conjunction with the certification number. For more information, read the information on the Walker Exhaust site

OEM Catalytic Converters

OEM (Original Equipment Manufacturer) catalytic converters are the exact replacements for what your vehicle came with from the factory. They are the most durable, contain the highest amount of precious metals, and are by far the most expensive option.

When installed on a new car, OEM converters are covered by an eight-year or 80,000-mile warranty. However, as a replacement part, they only carry the Federal/EPA-mandated warranty.

What Does a Catalytic Converter Do?

A catalytic converter is the unsung hero of your exhaust system. It takes harmful gases like carbon monoxide, nitrogen oxides, and unburnt hydrocarbons and transforms them into less harmful substances such as water vapor, carbon dioxide, and nitrogen. This is all thanks to a honeycomb structure coated with precious metals like platinum, palladium, and rhodium. These metals act as catalysts, triggering the chemical reactions that clean up your exhaust.

But not all catalytic converters are created equal.

If cost isn’t an issue and you want the longest-lasting solution, OEM is the way to go. That said, EPA and CARB converters can also effectively keep your check engine light off and control emissions if the underlying issues that caused the original failure are addressed.

Why Do Catalytic Converters Fail?

Catalytic converters are designed to last the life of your vehicle, but certain conditions can cause premature failure:

Overheating: When unburnt fuel enters the converter, it can overheat and damage the catalyst. This happens when precious metals clump together, reducing the surface area needed for the chemical reactions that clean your exhaust.

Contamination: Oil mist or antifreeze can coat the catalyst, preventing it from interacting with exhaust gases. This drastically reduces efficiency and can lead to failure.

Engine Management Issues: The most common culprit. Faulty oxygen sensors, air-fuel ratio sensors, vacuum or exhaust leaks, and engine misfires can overload the converter, causing overheating or contamination.

Replacing a Catalytic Converter

Before replacing a catalytic converter, it’s critical to address the root cause of the failure. If you don’t, you risk damaging the new converter and triggering the check engine light again. Common fixes include:

• Replacing sluggish O2 sensors.
• Cleaning or replacing mass airflow sensors.
• Fixing exhaust or vacuum leaks.
• Ensuring the PCV and EGR valves are in good working order.

What If the Check Engine Light Comes On After Replacement?

If your check engine light illuminates after installing an aftermarket converter, don’t panic. The issue might be with the engine’s long-term fuel trims. Catalytic converters operate within a narrow three-way emissions window, and fuel trims that are off by more than 10% can cause trouble.

Here’s what to do:

Disconnect the battery for 10 minutes to reset the fuel trims.
Check for unresolved issues like leaks or faulty sensors.
Make sure all related codes are addressed.

If the light persists, it’s likely that the original issue that damaged the first converter wasn’t fixed.

The Take-Aways From This Article

Whether you go with an EPA, CARB, or OEM catalytic converter, the key to success is solving the underlying engine problems that caused the original failure. Each type has its pros and cons:

EPA: Affordable and durable for most states.
CARB: A legal must-have for stricter states, with superior quality.
OEM: The ultimate in durability and performance, but costly.

©, 2024 Rick Muscoplat