Catalytic Converter Replacement and California Smog Check: What Rancho Cordova Drivers Need to Know

Catalytic-converter theft and replacement have become major concerns for California vehicle owners. If your catalytic converter was stolen, damaged, or replaced with an aftermarket unit, you may be wondering:

Will my vehicle still pass a California Smog Check?

The answer depends on whether the correct converter is installed and whether it meets California requirements.

California's Bureau of Automotive Repair states that a replacement catalytic converter must either be an original equipment manufacturer (OEM) converter or a California Air Resources Board-approved aftermarket converter with an Executive Order number that meets the exact requirements for the vehicle.

What Does the Smog Inspector Check on a Catalytic Converter?

A California Smog Check can include a visual inspection of the vehicle's emissions-control system in addition to the applicable functional, OBD, or tailpipe portions of the inspection.

For catalytic converters, BAR's Smog Check Manual requires inspectors to verify that the required converters are present and appear properly installed. That includes checking the number and location of the converters and looking for tampering or defects.

So a vehicle can have a problem during Smog Check even if the check engine light isn't currently illuminated.

Can I Install Any Aftermarket Catalytic Converter?

No.

This is particularly important in California.

BAR states that a replacement converter must be either:

• The correct OEM catalytic converter, or

• A CARB-approved aftermarket catalytic converter with the appropriate Executive Order, or EO, number for the vehicle.

The aftermarket converter has to meet the requirements for the specific vehicle application.

A catalytic converter being advertised as "universal" or physically fitting underneath the vehicle doesn't necessarily mean it complies with California requirements.

What Is a CARB Executive Order Number?

CARB evaluates certain aftermarket emissions-related parts and can exempt qualifying products from California's anti-tampering restrictions.

Approved aftermarket catalytic converters have identifying information associated with a CARB Executive Order (EO).

BAR's inspection procedures state that California aftermarket catalytic converters installed since January 1, 2009 are required to bear an EO number.

That identifying information allows an inspector to determine whether the converter is approved for the particular application.

I Bought a Catalytic Converter Online. Will It Pass Smog?

Don't assume it will.

Before purchasing an aftermarket converter, verify that the exact part is CARB-approved for your specific vehicle.

Two converters can look nearly identical while having different approved applications.

The correct converter can depend on vehicle characteristics such as model year, engine, emissions certification, and other application information.

Buying the wrong converter simply because it is less expensive can become costly if the vehicle later cannot pass its Smog Check.

My Catalytic Converter Was Stolen. What Should I Do?

BAR recommends having the replacement installed through an appropriately licensed automotive repair facility.

The replacement needs to be the correct OEM converter or a CARB-approved aftermarket converter meeting the requirements for the vehicle.

BAR also says the replacement should be installed before the vehicle's next Smog Check.

If an appropriate converter is difficult to locate or on back order, BAR recommends contacting the vehicle manufacturer or the Smog Check Referee for assistance.

Can a Catalytic Converter Theft Shield Cause a Smog Failure?

It can if it is installed incorrectly.

Catalytic-converter shields, cages, cables, and other anti-theft devices can help discourage theft, but BAR specifically warns that the device must not modify or damage the converter or prevent required identifying information from being visible.

BAR also says the theft-prevention device should not be welded or attached directly to the catalytic converter.

A properly installed theft-prevention device should therefore preserve access to the identifying information an inspector needs to see.

Can I Paint or Engrave My Catalytic Converter?

BAR recommends engraving or etching a VIN or license-plate number onto a converter as one possible theft deterrent.

Bright paint can also be used, but BAR cautions that the paint should not cover required identifying information.

The goal is to deter theft without interfering with the converter or its required markings.

Why Can a Vehicle Fail Even With a New Catalytic Converter?

Installing a new converter doesn't automatically guarantee a passing Smog Check.

Possible issues include:

• The converter isn't approved for that vehicle.

• Required identifying information cannot be verified.

• The converter is installed incorrectly.

• The vehicle has another emissions-system problem.

• The check engine light is on.

• The vehicle's onboard diagnostic system detects a fault.

• Other required emissions equipment is missing or modified.

BAR states that a vehicle will not pass if its check engine light is illuminated because of an emissions-system problem.

Proper diagnosis is important before assuming that replacing the converter alone will solve an emissions problem.

What About Performance Parts and Tuners?

Catalytic converters aren't the only aftermarket components that can affect a Smog Check.

BAR's inspection procedures include verification requirements for numerous modified or aftermarket emissions-related components. Examples can include certain camshafts, engine modifications, tuning devices, and other components that affect the emissions-control configuration.

BAR also advises owners with modified vehicle software to restore it to the manufacturer's original configuration or an applicable CARB-approved version before the Smog Check. Modified or non-approved software can cause a failure.

What If My Car Has an Engine Swap?

An engine change is a different situation from an ordinary replacement catalytic converter.

BAR currently requires vehicles with engine changes to receive their initial inspection at a Smog Check Referee Center. If the vehicle complies, a BAR Referee label is placed in the engine compartment.

Future Smog Checks can then generally be performed at a regular Smog Check station according to the information on that Referee label.

Simply replacing an original engine with an identical configuration is treated differently from an engine change.

Does a STAR Station Use Different Catalytic Converter Rules?

The emissions requirements themselves don't become different simply because a vehicle is directed to a STAR station.

STAR certification relates to the station.

BAR says STAR stations meet higher inspection-performance standards and can inspect vehicles that DMV directs to STAR stations, including gross-polluting vehicles.

If your DMV renewal notice says "Smog Certification Required at a STAR station," you need to use a STAR-certified station.

Smog Tech Pros is STAR Certified.

Frequently Asked Questions

Will an aftermarket catalytic converter pass smog in California?

It can, provided it is a CARB-approved aftermarket converter with the appropriate Executive Order and meets the exact requirements for the vehicle. An appropriate OEM converter is also acceptable.

Does a catalytic converter need a CARB number?

BAR states that aftermarket catalytic converters installed in California since January 1, 2009 must bear an Executive Order number.

Can a catalytic converter shield make my car fail smog?

A properly installed device should not modify or damage the converter or hide required identification. BAR warns that a vehicle can fail if the device damages or modifies the converter or prevents required information from being visible.

Can I weld a theft shield directly to the catalytic converter?

BAR advises that theft-prevention devices should not be welded or attached directly to the catalytic converter.

My converter was stolen and the correct replacement is backordered. What can I do?

BAR recommends contacting the vehicle manufacturer or the Smog Check Referee for assistance with a hard-to-find replacement converter.

Can Smog Tech Pros perform a STAR Smog Check?

Yes. Smog Tech Pros is a STAR Certified Smog Check station.

Need a Smog Check in Rancho Cordova?

If you've replaced a catalytic converter or simply need your California Smog Check completed, visit:

Smog Tech Pros
10751 Folsom Blvd
Rancho Cordova, CA 95670
916-638-4700

STAR Certified • No Appointment Necessary • Free Retest Included

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For customers who want to verify the requirements directly, see the California BAR catalytic-converter guidance and California BAR Smog Check guide.