P1421: Catalyst Damage
MediumPowertrainCatalytic Converter
What does P1421 mean?
P1421 is a diagnostic trouble code indicating "Catalyst Damage". The catalytic converter in your exhaust system is not converting harmful gases as efficiently as required. This affects emissions and may indicate the converter is failing or there is an upstream issue.
Common causes
- Aging catalytic converter
- Engine misfire damaging the converter
- Oil or coolant entering the exhaust
- Faulty downstream O2 sensor giving false reading
What should you do?
Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.
Get a diagnosis for YOUR car
Code P1421 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.