Can my catayltic converter go bad and not show any codes

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! Yep, a **catalytic converter can clog up without throwing a code**—at least, not right away. If it’s partially restricted, your engine can rev, but the exhaust can’t flow freely, choking off power, especially at higher speeds. Eventually, you might see a **P0420 (catalyst efficiency) code**, but not always. A quick test? Try **revving the engine in park**—if it struggles to climb RPMs or sounds wheezy, the cat could be clogged. A shop can confirm with an **exhaust backpressure test** or by temporarily loosening the exhaust before the cat to see if power improves. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.