Catalytic Converter Concerns

NOTICE: Due to the rise of Catalytic Converter Thefts, the Smog Check Referee Program has been receiving a high number of inquiries around Catalytic Converters. For this reason, we have updated our content with information from the most common inquiries we are contacted about. Review the content and links below prior to contacting the BAR Smog Referee program.

Catalytic Converters (CATs) are a key component in controlling vehicle emissions, and periodically may need replacement. Your local muffler shop has the resources needed to identify the proper CAT for your vehicle. Check with your vehicle manufacturer, dealer, parts retailer, or repair shop for CAT availability and review all information on this page prior to calling the Smog Check Referee Program.

Honda Accord SULEV Catalytic Converter 

If you are in need of a catalytic converter for your 2000-2007 Honda Accord SULEV, please see our Honda Accord page.

Cost Concerns

The Smog Check Referee Program has no control over the cost of parts. If you are seeking financial assistance for repairs, the Consumer Assistance Program (CAP) may be an option for you. You can call them at 866-272-9642 to learn more about their program and eligibility requirements.

Smog Check Referee Appointment Requirements:

  1. For 1996 and newer heavy duty trucks and motorhomes, verify whether the vehicle is Pre-OBD II or OBD II. Most Pre-OBD II vehicles do not require a BAR label or a Referee appointment. See below for more details.
  2. Engine Family Number (EFN) – ARB describes where you can find this information or you can click the following link to watch a video that can assist you in locating the emissions control label on your vehicle which would have the EFN noted. Here is a video that shows where the EFN is on an emmisions control label.
  3. Confirmation that the vehicle’s dealer does not have the part available and the repair shops have exhausted all resources including the information provided on this page. If Referee assistance is still required, you must have the part number of the required catalytic converter from the vehicles manufacturer ready.

Pre-OBD II Vehicles | Trucks, Vans and Older Vehicles

Pre-OBD II vehicles do not stop at 1995 and older. One way to determine if your vehicle is Pre-OBD II is to check your emissions label. If it states OBD I Certified, then it is a Pre-OBD II vehicle and does not need to see the Smog Referee (see image below).

Here is an image of a 2005 heavy duty vehicle’s VECI that states that the vehicle is OBD I

Common Vehicles

Some gasoline powered 1996 and newer medium/heavy duty vehicles are OBD I certified (Pre-OBD II) and do not have a rear oxygen sensor. If your vehicle is one of the following listed below, there is a high likelihood that your vehicle will be Pre-OBD II. Pre-OBD II do not need to see a Smog Referee, except for some very rare circumstances

  • Chevy/GMC: 2500, 3500, 4500, 5500
  • Ford: F-250, F-350, F-450, F-550, E-250, E-350, E-450, E-550
  • Ram: 2500, 3500, 4500, 5500
  • And heavier weight classes

Vehicles 1995 or older

Most, but not all, vehicles that are of 1995 and older will be Pre-OBD II. Pre-OBD II typically do not need to see a Smog Referee, except for some very rare circumstances.

Pre-OBD II Smog Technicians Guide

For Pre-OBD II Vehicles, inspectors shall use the EO number to verify if the CAT falls within the correct vehicle category- PC-1, PC-2, T-1, T-2. Refer to ARB’s Web site for a separate Pre-OBD II EO Listing containing the EO numbers and corresponding vehicle categories. Below are some additional information to help you in this process:

  • Inspectors are not required to check specific vehicle applications using the series or part numbers.
  • Pre-OBD II vehicles do not stop at 1995 and older. Refer to the VECI label to see if a vehicle is OBD I or OBD II.
  • The Magnaflow D-193-105 P/N 339301 is a T1 approved torpedo catalytic converter for Pre-OBD II Ford vehicles and coverage is not limited to 1995 and older. 
  • For more information on Pre-OBD II Vehicles, please refer to page 40 of the BAR Smog Check Manual (2017).

O2 Sensors and Catalytic Converter Installation Requirements

When installing an aftermarket CAT on your vehicle, we suggest using an OEM (original equipment manufacturer) 02 sensor. Aftermarket 02 sensors have been known to cause check engine lights when used with some aftermarket CATs. If a check engine light is on even after an acceptable aftermarket CAT has been installed, the vehicle will not pass smog. In addition, O2 sensors will also need to remain in the same configuration. Relocating the 02 sensor is not acceptable.

Difficulty finding Approved Catalytic Converter

Please check with a muffler or exhaust shop if your CAT is hard to find. Some muffler shops have access to various distribution warehouses that have the CAT’s that the Smog Referee’s have provided to you. If the correct CAT for your vehicle cannot be found and is confirmed unavailable, you may be able to qualify for a Limited Parts Exemption. Refer to the PLS process to learn more.

Diesel Catalytic Converters

There are no ARB-approved Diesel catalytic converters. Check with your local manufactures dealer for a catalytic converter.​ Reach out to us for a Limited Parts Exemption only if you have a missing Diesel catalytic converter and are on your biennial Smog Check year. A Limited Parts Exemption cannot be issued if you are going through a transfer of ownership.

California Air Resources Board (CARB) links

Most questions and concerns regarding aftermarket Catalytic Converters can be clarified by using the helpful California Air Resources Board (CARB) links below:

CARB Aftermarket Catalytic Converter Database

CARB Complete List of Aftermarket Catalytic Converters EOs

CARB FAQs – Aftermarket Catalytic Converters

If you still have questions regarding Catalytic Converters, visit our Catalytic Converter FAQ page for more information.

Revised: September 2021