Why Direct-Fit Matters on an Accord

We focus on direct-fit catalytic converters that match your factory pipe routing, flange positions and O₂ sensor locations. That means:

• No cutting or welding in most applications
• Correct catalyst volume and loading for your engine and emissions level
• A much better chance of passing your next emissions or smog inspection

You’ll see both standard/OEM-grade EPA units for 49-state vehicles and CARB-certified units for California-style states.

1. Watch for Common Symptoms

• Check Engine Light: Codes like P0420 / P0430 (“catalyst efficiency below threshold”).
• Failed Emissions / Smog Test: High HC, CO or NOx even after a tune-up.
• Loss of Power: Car feels “plugged up”, especially at highway speeds or under load.
• Poor Fuel Economy: Noticeable drop in MPG with no other obvious cause.
• Rattling from the Converter: Broken catalyst substrate rattling inside the shell.
• Strong Sulfur / “Rotten Egg” Smell: Sign of a converter overheating or contaminated by excess fuel.

One symptom alone doesn’t always confirm a bad cat, but several together (especially with P0420/P0430) are strong indicators.

2. Rule Out “Cat Killers” First

If you install a new converter on a car with an unresolved engine problem, the new unit can fail early.

• Fix any misfire codes (P0300–P030x).
• Address rich/lean fuel trim codes (P0171, P0172, etc.).
• Check for oil burning or coolant consumption that can contaminate the catalyst.
• Inspect for exhaust leaks ahead of the converter (manifold, flex pipe, gaskets).

Once those issues are corrected, if the catalyst-efficiency code keeps coming back, it’s usually time for a new converter.

3. Quick Drive Test (Backpressure/Performance)

On many Honda Accord models, a severely plugged cat will show up as:

• Normal idle, but the car will not rev freely under load.
• Power drops off as RPM increases (feels like you’re towing something heavy).
• The converter shell may get very hot if it’s severely restricted (do not touch).

A professional shop can confirm with a backpressure test or by comparing upstream/downstream O₂ sensor readings, but these drive-feel symptoms are good clues for a DIY owner.

4. When You’re Confident the Converter Is the Problem

Before ordering, gather the following:

• Model year, engine size, transmission type (manual/CVT/auto).
• VIN (last 8 digits are especially helpful).
• Emissions label info under the hood:
  • “Federal / EPA” vs “California emissions”
  • Test group / EFN (emissions family number) if in a California-style state
• State where the vehicle is registered (regulations differ).

With that info, you can confidently choose from the 49-state or California sections below or contact us for confirmation.

49-State & Canada (EPA) Vehicles

If your Honda Accord is registered in a federal emissions state (most of the U.S. and Canada) and the under-hood label does not mention California or “CARB”, you’ll normally use a 49-state/EPA-certified direct-fit converter.

• Product titles often say “49 State & Canada” or “Federal (Exc. CA/NY/CO)”.
• Available in standard grade and higher-load OEM grade catalyst versions.
• Generally lower priced than CARB units due to less stringent certification requirements.

California, New York, Colorado & Other CARB-Style States

If your Accord is registered in California, New York, Colorado or another state that follows California-style emissions rules, the converter must be CARB-certified with a matching Executive Order (EO) number.

• Look on the product page for an EO like D-193-157, D-193-140, etc.
• The EO must match your vehicle’s emissions family / test group printed on the under-hood label.
• The converter body itself will have the EO number etched or stamped into it.

Special Case: SULEV / PZEV Honda Accord Models

Some Accord trims are built to SULEV / PZEV ultra-low emissions standards. These cars require specific high-load converters that are different from standard EPA or “regular” California units.

• Check your emissions label for “SULEV” or “PZEV”.
• These applications will usually have a dedicated part number and EO reference.
• Always verify EFN/test group and year/engine before ordering.

In the product listings linked above, SULEV/PZEV units are clearly marked so you can avoid the common mistake of installing a standard cat on a SULEV car.

Quick State-Selection Checklist

1. Find the emissions label under the hood (usually on the radiator support or strut tower).
2. Check what it says:
   • “Federal / EPA” → use the 49-state search link.
   • “California” or “CARB” → use the California/NY/CO link with matching EO.
   • Mentions “SULEV/PZEV” → look for SULEV/PZEV-specific listings in the CA search results.
3. Confirm the state of registration:
   • CA, NY, CO and other California-style states require CARB-legal converters.
   • Most other states accept EPA 49-state converters.
4. Match year, engine size and position (front, rear, underbody, bank 1/2).
5. Still unsure? Use the product Q&A or contact us with VIN + emissions info.