Product images and videos are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.
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Overview
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Vehicle Symptoms
- Check engine light on (P0420/P0430)
- Rotten egg smell from exhaust
- Failed emissions test
- Decreased fuel economy
- Sluggish acceleration
Diagnostic Codes
- P0420 – Cat Sys Efficiency Below Threshold (B1)
- P0430 – Cat Sys Efficiency Below Threshold (B2)
Relevant Conversations
- P0420 diagnostic code help
- Magnaflow 21-681 catalytic converter review
- Direct fit cat converter replacement guide
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- P0420 vs P0430 catalytic converter fix
- Catalytic converter clogged symptoms
- Best catalytic converter for 2005 Honda Accord
- Check engine light after cat replacement
- Will P0420 clear with new cat?
- Magnaflow 21-681 installation YouTube
Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.
Fitment
Fitment Guaranteed
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Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.
Available on iOS & Android
Specifications
| Brand | Magnaflow |
| Part Number | M001 21-681 |
Videos
Install a Magnaflow Catalytic Converter, Universal Fit
Magnaflow 50 State Legal CAT Converter Install on 5.3L GM Pickup
2011-2014 F150 5.0L Magnaflow Direct Fit Federal Catalytic Converter Assembly Install
How to Choose a Catalytic Converter by Magnaflow - SummitRacing.com
How to Select the Correct Catalytic Converter - California, Colorado and New York | MagnaFlow
Magnaflow Catalytic Converter Features
Magnaflow Catalytic Converters - 49 State Legal Review - SEMA 2013
About MOTORMIA
Buy with Confidence
Returns & Fitment
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.
Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.
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