The Lemon IndexThe catalytic converter on bank 1 isn't cleaning the exhaust as well as it should.
Drive on, get it checked. You can usually keep driving. Have the code read at your next service or within a few weeks.
Worn-out catalytic converter. Then: faulty downstream O2 sensor; exhaust leak.
Owners named P0420 in 359 complaints to the U.S. government, most often on the Kia Soul.
Models that report it most
Complaints that name P0420, by model. Raw counts, not a failure rate: popular models get more complaints. Tap a model for its years, mileage and what owners say fixed it.
P0420 by model: P0420 Kia Soul (80) · P0420 Nissan Altima (19) · P0420 Ford Focus (16) · P0420 Hyundai Tucson (12) · P0420 Honda Odyssey (11) · P0420 Ford F-Series (10) · P0420 Honda Pilot (10)
Years owners report it on most: 2015 Kia Soul · 2016 Kia Soul · 2014 Kia Soul · 2013 Kia Soul · 2002 Nissan Altima · 2003 Nissan Altima
The details
What P0420 means
The catalytic converter on bank 1 isn't cleaning the exhaust as well as it should. The car usually drives normally, but it can fail an emissions test.
Can I drive with P0420?
Drive on, get it checked. You can usually keep driving. Have the code read at your next service or within a few weeks.
18% of the owner complaints that name P0420 also say the car stalls or shuts off. A complaint can describe more than one problem, so this doesn't prove the code caused it.
Common causes of P0420
- Worn-out catalytic converter
- Faulty downstream O2 sensor
- Exhaust leak
- Misfires or oil burning that damaged the converter
A shop should confirm the cause with a scan and tests before replacing parts.
What owners describe
- Stalls or shuts off: 18% of complaints
- Shakes, runs rough or misfires: 15% of complaints
- Loses power or goes into limp mode: 15% of complaints
- Uses or leaks oil: 12% of complaints
Share of complaints naming the code whose text also mentions each problem.
Model years that report P0420 most
2015 Kia Soul (20), 2016 Kia Soul (16), 2014 Kia Soul (14), 2013 Kia Soul (13), 2002 Nissan Altima (9), 2003 Nissan Altima (7).
Related codes
P0421 P0418 P0411 P0410 P0430 P0406 P0405 P0404
Quick answers
What does P0420 mean?
Catalyst System Efficiency Below Threshold (Bank 1). The catalytic converter on bank 1 isn't cleaning the exhaust as well as it should. The car usually drives normally, but it can fail an emissions test.
Can I drive with P0420?
Drive on, get it checked. You can usually keep driving. Have the code read at your next service or within a few weeks.
What causes P0420?
Worn-out catalytic converter; Faulty downstream O2 sensor; Exhaust leak; Misfires or oil burning that damaged the converter.
Counts: NHTSA owner complaints whose text names P0420. A complaint is an owner's report, not a diagnosis. Meanings: the standard SAE J2012 definitions in our own words; manufacturer codes only where verified for that make. General information, not repair advice for your car.