Catalytic converter replacement can be one of the most arduous repairs a shop takes on. It is not that the repair itself is overly complicated; it is the paperwork, laws and warranty issues that can be the real headache.
Below are the 10 commandments of a catalytic converter replacement handed down from the EPA.
- If the replacement is not required by a state or local program, both customer and technician must sign a statement concerning why the converter was replaced. (Manufacturers either provide such a statement with the catalytic converter or have an example in their catalogs.)
- If the replacement is required by a state or local program, the technician must keep a copy of the statement or order by the program representative.
- The invoice for replacement must include the customer’s name and complete address, the vehicle’s make, model year and mileage, as well as the reason for catalytic converter replacement.
- Retain copies of the invoices and statements for six months and the replaced converters for 15 days (converters must be identified or marked as to which customer’s car they came from).
- Install the catalytic converter in the same location as the original.
- Install the same type of catalytic converter as the original — oxidation, 3-way or 3-way plus oxidation (dual-bed). This information is sometimes available on the emission tune-up label or from the manufacturer’s application catalog.
- Install the proper converter for the vehicle as determined and specified by the converter manufacturer. There are engine-size and vehicle-weight limitations that make it inappropriate to install certain converters on certain vehicles. Newer vehicles with On-Board Diagnostic (OBD) systems may not always operate properly with certain aftermarket products. Therefore, the catalog should always be consulted for the correct application.
- The catalytic converter replacement must always be properly connected to any existing air injection components.
- Install all the other required converters the vehicle would have originally come with unless the converter manufacturer has stated in writing that the aftermarket converter is designed to replace more than one converter.
- For a new aftermarket catalytic converter replacement, the installer must fill out the warranty information card supplied by the manufacturer and give it to the vehicle owner or operator.
Violating the EPA rules is a breach of federal law since noncompliance is likely to increase the amount of pollution coming out of the vehicle. Penalties for violations by individuals, service or repair shops or fleet operators can be up to $2,500 per violation. (Each improper installation is considered a violation.) Additionally, new-car dealers can be penalized up to $25,000 per violation. Any person who causes a violation could be subject to the same penalty as the technician. 
New York State Environmental Conservation Law regarding catalytic converter installation mandates a minimum penalty of $500 for a first violation, and up to $26,000 for each subsequent violation. Failure to maintain complete records or submit reports may also result in a violation.
The conditions under which the catalytic converter replacement was installed is of great importance to the part manufacturer. Even simply using the wrong part on a vehicle may allow the converter manufacturer to not honor the 25,000-mile or the 5-year/50,000-mile warranty.
For vehicles in California and other states that require California Air Resources Board (CARB)-mandated emissions equipment, the rules are different. All of the same mandates apply, but they are much more strict about the replacement converter being CARB-compliant. Also, the CARB rules are based on a one-for-one replacement strategy, and the addition or consolidation of converters is forbidden.
The greatest difference between states is the length of time needed to keep documentation. California and New York require paperwork be kept for at least four years.
Also, it is important to check local and state laws before installation. New York, for instance, enacted a ban on installing used catalytic converters on vehicles.
