Catalytic converter warranty coverage
The federally mandated emissions warranty that comes with your vehicle covers your catalytic converter against failed emissions tests and manufacturing defects during its first eight years or 80,000 miles (whichever comes first).
This warranty consists of two parts. Performance warranties last for two years or 24,000 miles and cover any repair required to get your vehicle to pass a state emissions test. Design and defect warranties last eight years or 80,000 miles and cover specific critical components, including the catalytic converter, against defects in materials or workmanship.
| Federally mandated warranty | Coverage period | What’s covered |
|---|---|---|
| Performance warranty | 2 years/24,000 miles | Repair or replacement of most emissions-related parts when a vehicle fails an approved emissions test |
| Design and defect warranty | 8 years/80,000 miles | Repairs or replacement of catalytic converters, ECU systems or OBD systems that fail due to defects in materials or workmanship |
If your catalytic converter fails after eight years or 80,000 miles, you are responsible for fixing it.
Once this warranty expires, though, any other warranty coverage you may have will only cover the mechanical problems that cause your catalytic converter to fail — not the catalytic converter itself. For example, an engine problem that fouls your catalytic converter could still be covered under your powertrain warranty, even if your catalytic converter isn’t.
Catalytic converter warranty exclusions
It’s worth pointing out that warranties only cover failures due to factory defects. That means your warranty won’t cover stolen or removed converters. If you want protection from this unforeseen expense, you will need to have comprehensive auto insurance.
Other common exclusions include:
Physical damage from accidents, road debris or bottoming out your vehicle
Normal wear and tear beyond the warranty period (eight years/80,000 miles for federal coverage)
Preexisting conditions from previous owners
Consequential damages, such as damage to other vehicle components caused by a failed catalytic converter
How major automakers handle catalytic converter warranties
All major automakers must comply with the same federal emissions warranty requirements, but the claim process will vary from brand to brand. The first step is generally visiting your dealer to get a diagnosis for your vehicle.
If a catalytic converter failure occurs within the federal emissions warranty period, the manufacturer will generally require documentation showing the vehicle was properly maintained and that the failure was not caused by misuse, accident damage or unauthorized modifications.
What voids your catalytic converter warranty
Several specific actions can void your catalytic converter warranty:
Modifications to exhaust or emissions systems, including removing, tampering with or bypassing the catalytic converter
Installing noncompliant parts, such as aftermarket converters that aren't CARB-approved (in California and other CARB states) or EPA-compliant
Failure to maintain your vehicle according to the manufacturer's recommended service schedule, particularly skipping oil changes or ignoring check engine lights
Using improper fuel types or octane ratings below manufacturer specifications
Unauthorized installation by noncertified shops or failing to provide proper documentation of the original installation
» MORE: Typically covered components
Does an extended warranty cover your catalytic converter?
Most extended auto warranty companies don’t cover catalytic converter repairs or replacements, but like your factory warranties, they may cover issues that caused your converter to fail.
Always check the fine print and ask your representative which plan includes these issues so you don’t have to pay more out-of-pocket expenses if you ever have to replace your catalytic converter due to a manufacturer failure.
“A couple of months into buying the car..even after having it professionally inspected, the catalytic converter went haywire,” wrote Beverly, a reviewer from Michigan. “I thought my policy would cover it...Wish I would have known more about what it did and did not cover when the car dealer sold it to me, would not have bought it.”
I thought my policy would cover it...Wish I would have known more about what it did and did not cover when the car dealer sold it to me, would not have bought it.”
How to file a warranty claim for your catalytic converter
Filing a federal emissions warranty claim for your catalytic converter follows these steps:
Verify warranty eligibility: Confirm your vehicle is within the two-year/24,000-mile performance warranty period or the eight-year/80,000-mile design and defect warranty period. For the warranty to apply, the vehicle must fail an approved emissions test (performance warranty) or have a defective part (design and defect warranty).
Gather required documentation: Collect your vehicle's warranty paperwork, proof of ownership and maintenance records to demonstrate proper care. If the vehicle has failed an emissions test, you’ll also need to bring a copy of the test report.
Take your vehicle to an authorized dealer: For federal emissions warranty claims, you must take your vehicle to a facility authorized by the vehicle manufacturer to give them the opportunity to diagnose and repair the issue.
Allow diagnosis and inspection: The authorized facility will inspect your catalytic converter and diagnose whether the failure is covered under warranty terms.
Complete the repair at no cost: If approved, the manufacturer covers the replacement or repair costs under the federal emissions warranty.
Keep all documentation: Save service records and receipts from the repair for your records.
Eligibility requirements for warranty claims
To qualify for federal emissions warranty coverage on your catalytic converter, you must meet these requirements:
Within warranty period: Your vehicle must be within eight years or 80,000 miles for catalytic converter coverage, whichever comes first.
Failed emissions test or defective part: Your vehicle must have failed an approved emissions test administered by a certified testing facility to get coverage under the federal Performance emissions warranty. To qualify under the design and defect warranty, a qualified automotive technician needs to demonstrate that your catalytic converter has a manufacturing defect.
Proper maintenance: The vehicle must be maintained according to manufacturer specifications, though proof of maintenance is not required if an emission control component is found defective in materials or workmanship.
Manufacturing defect: The failure must be due to a defect in materials or workmanship, not from damage, misuse or lack of maintenance.
No disqualifying modifications: The vehicle's emissions system must not have been tampered with or modified in ways that void warranty coverage.
Warranty coverage for aftermarket catalytic converters
Aftermarket catalytic converters come with warranty coverage, though terms vary by manufacturer and state. Most offer 25,000 miles of coverage for emissions performance and five years or 50,000 miles for materials and workmanship. In California, aftermarket converters must be warranted for five years or 50,000 miles to comply with California Air Resources Board (CARB) standards.
To maintain coverage, the converter must be properly installed and maintained according to specifications. Warranties typically exclude damage from accidents, improper installation or engine problems that damage the converter.
Before purchasing, verify that the converter is approved for your vehicle's specific year, make, model and engine configuration. Reputable sellers should provide this information upfront, and repair shops can help confirm compatibility before installation.
Do you live in a CARB-compliant state?
Currently, 18 states and Washington, D.C. follow CARB standards. If you live in one of these jurisdictions, make sure any aftermarket unit you buy is CARB-compliant. California emissions regulations are stricter than federal requirements, and installing a converter that isn't approved can cause your vehicle to fail a smog inspection and may void warranty coverage.
How much does it cost to fix your catalytic converter?
Several factors affect the cost of fixing your catalytic converter, including your car’s make and model and what kind of fix you need:
A complete replacement can range from around $1,000 to over $4,000, based on our research.
Fixing your existing catalytic converter can theoretically cost less, but it’s not always a viable option. (In some cases it’s not possible, and even if it is, it may not save you money versus getting a replacement.)
Factors that affect the cost to fix your catalytic converter
The total expense of fixing or replacing a catalytic converter depends on several key elements:
Vehicle make and model: Luxury or foreign cars often require more expensive parts or specialized labor.
Extent of damage: Whether the converter is fully clogged, melted or only slightly degraded can influence repair vs. replacement options.
Labor rates: Regional labor costs can significantly affect your total bill.
Part availability: OEM vs. aftermarket parts vary in price and availability, with OEM parts generally costing more.
Additional damage: Related component failures, like a faulty oxygen sensor or engine misfire, can add to the overall repair bill.
Symptoms of a failing catalytic converter
A failing catalytic converter can lead to noticeable symptoms in your vehicle's performance and emissions. Common signs include:
Reduced engine performance, including sluggish acceleration and difficulty maintaining speed
A rotten egg smell caused by sulfur buildup
Check engine light illumination
Decreased fuel efficiency
Dark exhaust smoke or excessive heat under the vehicle
Factors that can shorten a catalytic converter's life include engine misfires, oil leaks, use of low-quality fuel or improper fuel additives, frequent short trips that prevent the converter from reaching optimal operating temperature, and physical damage from bottoming out the vehicle.
Regular engine maintenance — including timely oil changes, spark plug replacements and addressing check engine lights promptly — can help maximize your catalytic converter's lifespan.
» CONSIDER: Pros and cons of car warranties
FAQ
Is a catalytic converter covered under a powertrain warranty?
No, most powertrain warranties don't cover catalytic converters since they are considered part of your emissions system. Powertrain warranties are responsible for covering your transmission, axles and engine (the parts that make your car go).
How long is a catalytic converter covered under warranty?
Catalytic converters are covered under the federal emissions warranty for either eight years or up to 80,000 miles (whichever comes first). For your catalytic converter to qualify for warranty repairs in this time frame, it must have failed an emissions test or experienced manufacturing-related issues.
What voids a catalytic converter warranty?
A catalytic converter will not be covered by your warranty if issues arise from vehicle misuse or if the part has been stolen. Repairs are only covered by part-specific failures that are not your fault.
Does insurance cover a stolen catalytic converter?
Yes, comprehensive auto insurance covers catalytic converter theft. It will cover the cost of replacement and any related damages. If you only carry liability insurance, however, you will likely have to pay the replacement cost out of pocket.
How long should a catalytic converter last?
Catalytic converters should last at least 10 years on modern vehicles, and many function for 100,000 miles or longer. With proper vehicle maintenance, some owners never need to replace their catalytic converter during the vehicle's lifetime.
Can I transfer my catalytic converter warranty to a new owner?
Yes, you can transfer a catalytic converter warranty to a new owner. The federal emissions warranty follows the vehicle, not the owner. If a catalytic converter is still within the federal warranty period of eight years or 80,000 miles, a subsequent owner may be eligible for coverage as long as the vehicle meets all warranty requirements.
Article sources
ConsumerAffairs writers primarily rely on government data, industry experts and original research from other reputable publications to inform their work. Specific sources for this article include:
U.S. Environmental Protection Agency, “Frequent Questions related to Transportation, Air Pollution, and Climate Change.” Accessed Oct 12, 2026.
California Air Resources Board, "California Vehicle and Emissions Warranty Periods." Accessed Oct 12, 2026.
North Carolina Consumers Council, "The Federal Emissions Warranty is Often Overlooked When Your Vehicle Needs Emissions Fixes." Accessed Oct 12, 2026.
U.S. Environmental Protection Agency, “Emissions Warranties for 1995 and Newer Light-Duty Cars and Trucks Under 8,x500 Pounds Gross Vehicle Weight Rating (GVWR).” Accessed Oct 12, 2026.
California Environmental Protection Agency, “California Evaluation Procedures for New Aftermarket Catalytic Converters.” Accessed Oct 12, 2026.
Colorado Department of Public Health and Environment, “Aftermarket Catalytic Converters.” Accessed Oct 12, 2026.
California Air Resources Board, "States That Have Adopted California’s Vehicle Regulations.” Accessed Oct 12, 2026.
