Catalytic Converter California

The laws are very different for catalytic converters California. They have some of the strictest guidelines and laws that govern what can and cannot be done in their state. It is actually illegal to remove a cat that is working properly.  The cat is an integral part of the car’s exhaust system. The inside of this cylindrical unit is made of honeycomb shaped ceramic. The cat is typically situated between the muffler and the engine. It works to convert toxic gases that are emitted from the engine into less toxic, harmless gases before it is expelled through the car’s exhaust system and out into the air.


New C.A.R.B. requirements for Aftermarket Catalytic Converters in California.


New C.A.R.B. regulations (effective 1-1-09) change the requirements of aftermarket catalytic converters sold in CA. The new regulations require that catalytic converters meet low emission vehicle (LEV) standards, a significant improvement in performance over the current generation catalysts. 

These new regulations are limited to catalysts sold in CA, and do not effect catalysts sold in the other 49 states. 

In addition all aftermarket converters sold or installed in the state of California must bear an Executive Order (EO Tag) stamp issues by CARB (California Air Resources Board).

Discount Converter, Ltd. will be able to provide CA legal catalysts for the California market that meet all C.A.R.B requirements as they are approved by the California Air Resources Board.




Catalytic Converter in California is required to be placed on every legally registered vehicle in the state. The catalyst also has to be working. It is also illegal to replace a cat that is working properly. It is legal to replace a catalytic converter. California law allows it when the cat is no longer working well, or if it has failed the emissions test. It must also be replaced with a brand new unit that is in full compliance with the state’s laws and requirements.


Beginning July 10, 2008, no used converter can be legally advertised for sale, sold as replacement, or installed in California after this date.


The Air Resources Board’s (ARB) California Evaluation Procedures for New Aftermarket Non-Original Equipment Catalytic Converters (California Procedures) were adopted by the Board on August 19, 1988. An interim procedure, Optional Evaluation Procedures for New Aftermarket Non-Original Equipment Catalytic Converters, was set up to address requirements specific to catalytic converters for vehicles equipped with on-board diagnostics II (OBD II) systems and went into effect on December 2001. These regulations require new aftermarket catalytic converters to comply with requirements of Title 13, California Code of Regulations (CCR) section 2222(h) in order to be exempted from California’s anti-tampering law (Vehicle Code section 27156), thereby allowing them to be offered for sale, sold, installed or used in California.


The ARB adopted revised regulations and evaluation procedures in October 2007 for the approval of new aftermarket catalytic converters sold in California. The requirements apply to all new aftermarket converters produced for sale or sold in California after January 1, 2009. The requirements also sunset provisions allowing the sale of certified used catalytic converters beginning July 10, 2008. This means that no used converter can be legally advertised for sale, sold, or installed in California after this date.



The laws in this Western state are very tough on all automobile emissions and exhaust. When a cat is removed it has to be done while following all the strict guidelines for the state’s Air Resources Board. Not only do these laws stipulate the removal of the cat; they also set out the guidelines for the installation and even the sale of catalytic converter. The ARB laws also state that any of these units that are sold or installed have to be tested and also approved by the ARB or for some reason exempt. You will have to follow very specific guidelines and a set forth process to do so.


A bit of pain in the future for those of you in CA with older cars, and for the rest of you who don’t live here, I guess you can be thankful. My CRX needs to pass smog tests this year and after a few pretests and troubleshooting, the cat needs to be replaced to pass emissions. That would be fine, but on Jan 1, 2009, the wizards in Sacramento passed a new law banning the majority of aftermarket catalytic converters. After Jan 1, a cat you can buy in the other 49 states cannot be sold to CA. Because of this, I went from buying one to fit my CRX that would have cost ~$275 to one at the dealer for $592. (and then add the new 10-11% sales tax, and the doubling of the registration fees to that!).


The new law also bans the sale of used cats, forces autoshops to verify that the old converter really needed to be changed, and the serial numbers logged. I’m all for clean air and can handle replacing the cat, but this seems pretty ridiculous. The link below is for the CA air resources board discussing the new law, and though I didn’t spend more then about 15 minutes looking through there, the one thing I couldn’t find is why they needed this new law. If there is some issue that the aftermarket cats do not have the quality the OEMs ones do, then the car wouldn’t pass the emissions tests. Seems to me, another idiot on the state’s payroll decided to create a new law that costs the tax payers more money, creates more govt spending enforcing therse new laws, and does nothing.



It is best to not make any changes to your cat yourself. The general rule is to take it to a qualified mechanic and have them remove it or replace it. Make sure that you find a qualified and reliable mechanic who is very aware of the legal guidelines. If not, you may end up having to pay a huge fine.


What is the main reason most catalytic converter sold to California not legal?


If I go online to buy a catalytic converter, why is it NOT legal in California? And most of the vendor will NOT ship to California. WHY?? What is the main reason?
To make it simple at one time ago there was car made [out] of California state, when this owner took it to that state California it would not pass inspection for it could not meet the requirements, then another person who just had purchased a car [in] California an inspection done in California and passed so he drove to out state of California state and had the car inspected and it failed. Go figure different states – different inspection rules,- different methods and different equipment to check the inspections

Being aware of the state laws is very important, but you also must be aware of the federal organization the Environmental Protection Agency. They also have certain laws regarding the catalytic converter. California just has more that is added on to what the EPA sets forth.