The Lemon IndexThe catalytic converter on bank 1 isn't cleaning the exhaust as well as it should. Full P0420 page
10 owner complaints · one of 274 codes Ford F-Series owners name · 2% of Ford F-Series complaints that name a code (every car: 2.3%)
2006–2022 Ford F-Series · most: 2018 (4), 2020 (2), 2019 (2)
Ford F-Series owners named P0420 in 10 complaints to the U.S. government (NHTSA), most often on the 2018, 2020 and 2019 model years. The part they name most is the catalytic converter (7 complaints). Complaints are owner reports, not proof of a defect.
Ford F-Series model years that report P0420
Owner complaints naming P0420, by model year. Raw counts: years that sold more get more complaints, so this is each model year's record, not a failure rate.
What owners say caused it or fixed it
The most-named part is the catalytic converter, in 7 of the 10 complaints (70%). 7 of those mention it being replaced or repaired, and 2 say the problem came back afterwards. Next: engine software (a reflash) (5) and engine computer (ECM / PCM) (3).
- Catalytic converter7 complaints7 mention a repair or replacement, 2 of them say the problem came back · what Ford F-Series owners paid
- Software update (reflash)5 complaints4 mention a repair or replacement, 1 of them says the problem came back
- Engine computer (ECM / PCM)3 complaints2 mention a repair or replacement, 1 of them says the problem came back · what Ford F-Series owners paid
3 complaints mention a recall and 3 mention a warranty.
Counted from the owners' own words: a part counts when a sentence names it with a cause or repair word. What owners wrote, not a diagnosis. A shop should confirm the cause before replacing parts.
Symptoms owners describe with P0420
80% of these complaints say the check engine light came on.
- Loses power or goes into limp mode30%3 of 10 complaints
- Shakes, runs rough or misfires20%2 of 10 complaints
- Transmission slips or shifts hard20%2 of 10 complaints
Share of the complaints naming P0420 whose text also describes each problem. A complaint can describe more than one.
Codes owners report with it
P0430 5
Other codes named in the same Ford F-Series complaints, and in how many.
Repair costs
- Catalytic converter replacement$3,4884 bills · middle bill
Repair bills owners named in these 10 complaints (4 in all). Owner reports, not a quote: costs vary by shop and region.
Ford F-Series ECM (engine computer) replacement cost
Recalls on these Ford F-Series years
- Engine · 2022 · issued 2024
The engine intake valves may break while driving, which can result in engine failure and a loss of drive power. NHTSA 24V635000 - Engine · 2018, 2019 · issued 2019
During the previous repair, the block heater cable's splice connector may have been damaged. NHTSA 19V278000 - Engine · 2018, 2019 · issued 2018
Water and contaminants may get into the block heater cable's splice connector causing corrosion and damage. NHTSA 18V894000 - Engine · 2018 · issued 2017
The cylinder heads may have been machined without lubrication supply holes for the camshaft bearing journals. NHTSA 17V672000
4 recalls for the same systems (engine) on the Ford F-Series model years above. A recall for the same system isn't proof it's behind P0420. Recall work is free at any dealer: check a VIN at nhtsa.gov/recalls or with our VIN check.
Keep going
- P0420: meaning, causes and every car that reports it
- Ford F-Series reliability by year
- 2018 Ford F-Series problems and recalls
Other codes Ford F-Series owners report
P0720 P0722 P2112 P0707 P0706 P1702 P0016 P0721 P0705 P07F7
P0420 on other cars
Kia Soul (80) · Nissan Altima (19) · Ford Focus (16) · Hyundai Tucson (12) · Honda Odyssey (11) · Honda Pilot (10)
The details
How we count
We read every owner complaint in the NHTSA file whose text names this trouble code, and count the ones filed about this model (matched by the make, model and model year on the complaint). Mileage is what the owner entered on the form.
Parts: a complaint counts for a part when one of the owner's own sentences names that part together with a cause word (failed, bad, diagnosed, caused by, leaking ...) or a repair word (replaced, repaired, new, reprogrammed ...). "Came back" means the same complaint also says the problem returned or the repair didn't fix it. These are counts of what owners wrote, not a diagnosis, and one complaint can name several parts.
Complaints are reports, not proof of a defect, and most owners never file one. Popular models get more complaints, so the counts are not a failure rate. The code meaning is the standard SAE J2012 definition in our own words, or the carmaker's meaning where we verified it for that make.
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.
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
- Faulty downstream O2 sensor
- Exhaust leak
- Misfires or oil burning that damaged the converter
Check the complaints yourself
NHTSA complaint numbers (search them at nhtsa.gov): 11766891, 11750958, 11745592, 11742882, 11719515, 11642766, 11596379, 11588375, 11571630, 10532184.
Quick answers
What does P0420 mean on a Ford F-Series?
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.
Which Ford F-Series years have the most P0420 complaints?
In complaints to NHTSA, owners of the 2018 (4), 2020 (2), 2019 (2) Ford F-Series named P0420 most (10 complaints in all, 2006–2022). Raw counts, not a failure rate.
What fixes P0420 on a Ford F-Series?
Owners most often name the catalytic converter (7 of 10 complaints), then engine software (a reflash) and engine computer (ECM / PCM). That's what owners wrote, not a diagnosis: have a shop confirm the cause with a scan and tests before replacing parts.
Can I drive my Ford F-Series 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.
Sources: NHTSA owner complaints that name P0420 on the Ford F-Series, counted by The Lemon Index; NHTSA recalls; repair bills owners named. Meanings: SAE J2012 in our own words. Owner reports, not a diagnosis or repair advice for your car.