The Lemon IndexThe catalytic converter on bank 1 isn't cleaning the exhaust as well as it should. Full P0420 page
11 owner complaints · the #9 code Honda Odyssey owners name · 4% of Honda Odyssey complaints that name a code (every car: 2.3%)
2000–2019 Honda Odyssey · most: 2019 (6), 2018 (2), 2000 (2)
Honda Odyssey owners named P0420 in 11 complaints to the U.S. government (NHTSA), most often on the 2019, 2018 and 2000 model years. The part they name most is the catalytic converter (7 complaints). Complaints are owner reports, not proof of a defect.
Honda Odyssey 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 11 complaints (64%). 5 of those mention it being replaced or repaired, and 2 say the problem came back afterwards. Next: fuel injectors (6), fuel pump (3) and oxygen (O2) sensor (2).
- Catalytic converter7 complaints5 mention a repair or replacement, 2 of them say the problem came back · what owners paid
- Fuel injectors6 complaints5 mention a repair or replacement, 1 of them says the problem came back · what owners paid
- Fuel pump3 complaints2 mention a repair or replacement, 1 of them says the problem came back · what Honda Odyssey owners paid
- Oxygen (O2 / air-fuel) sensor2 complaints2 mention a repair or replacement, 1 of them says the problem came back · what 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
55% of these complaints say the check engine light came on.
- Loses power or goes into limp mode36%4 of 11 complaints
- Stalls or shuts off18%2 of 11 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
Other codes named in the same Honda Odyssey complaints, and in how many.
Repair costs
Honda Odyssey fuel pump replacement cost
Recalls on these Honda Odyssey years
- Fuel system, gasoline · 2018, 2019 · issued 2023
The fuel pump inside the fuel tank may fail. NHTSA 23V858000 - Engine · 2018, 2019 · issued 2023
Due to a manufacturing error, the connecting rod bearing in the engine may wear and seize, damaging the engine. NHTSA 23V751000 - Fuel system, gasoline · 2019 · issued 2021
The low-pressure fuel pump inside the fuel tank may fail. NHTSA 21V215000 - Fuel system, gasoline · 2018, 2019 · issued 2021
The fuel tank assembly installed by Braun may be susceptible to the fuel tank overfilling into the charcoal canister. NHTSA 21V010000 - Engine · 2019 · issued 2019
The timing belt teeth may separate from the belt. NHTSA 19V298000
8 recalls for the same systems (engine and fuel) on the Honda Odyssey 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
- Honda Odyssey reliability by year
- 2019 Honda Odyssey problems and recalls
Other codes Honda Odyssey owners report
U3000 P0740 P0730 P0301 P0304 P0303 P219A P0302 P3400 P3497
P0420 on other cars
Kia Soul (80) · Nissan Altima (19) · Ford Focus (16) · Hyundai Tucson (12) · Ford F-Series (10) · 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): 11753401, 11751060, 11739074, 11722388, 11712613, 11665515, 11654070, 11646780, 10569436, 10452063, 10145212.
Quick answers
What does P0420 mean on a Honda Odyssey?
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 Honda Odyssey years have the most P0420 complaints?
In complaints to NHTSA, owners of the 2019 (6), 2018 (2), 2000 (2) Honda Odyssey named P0420 most (11 complaints in all, 2000–2019). Raw counts, not a failure rate.
What fixes P0420 on a Honda Odyssey?
Owners most often name the catalytic converter (7 of 11 complaints), then fuel injectors and fuel pump. 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 Honda Odyssey 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 Honda Odyssey, 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.