The Lemon IndexThe catalytic converter on bank 1 isn't cleaning the exhaust as well as it should. Full P0420 page
80 owner complaints · the #1 code Kia Soul owners name · 41% of Kia Soul complaints that name a code (every car: 2.3%)
Middle of 119,000 miles · most between 89,000 and 145,000 (29 owners gave it)
Kia Soul owners named P0420 in 80 complaints to the U.S. government (NHTSA), most often on the 2015, 2016 and 2014 model years, at a middle of 119,000 miles. The part they name most is the catalytic converter (46 complaints). Complaints are owner reports, not proof of a defect.
Kia Soul 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.
Mileage when it happened
119,000 miles is the middle of what 29 owners entered. Half were between 89,000 and 145,000 miles.
The mileage on the complaint form, when the owner gave one.
What owners say caused it or fixed it
The most-named part is the catalytic converter, in 46 of the 80 complaints (57%). 24 of those mention it being replaced or repaired, and 10 say the problem came back afterwards. Next: engine software (a reflash) (11), pistons, rings or valves (11) and engine computer (ECM / PCM) (10).
- Catalytic converter46 complaints24 mention a repair or replacement, 10 of them say the problem came back · what Kia Soul owners paid
- Software update (reflash)11 complaints11 mention a repair or replacement, 4 of them say the problem came back
- Pistons, rings or valves11 complaints1 mentions a repair or replacement
- Engine computer (ECM / PCM)10 complaints8 mention a repair or replacement, 5 of them say the problem came back · what owners paid
- Oxygen (O2 / air-fuel) sensor7 complaints4 mention a repair or replacement, 2 of them say the problem came back · what owners paid
- Engine replaced or rebuilt6 complaints6 mention a repair or replacement, 2 of them say the problem came back · what Kia Soul owners paid
- Spark plugs4 complaints3 mention a repair or replacement, 2 of them say the problem came back · what owners paid
- Ignition coils3 complaints2 mention a repair or replacement, 1 of them says the problem came back · what owners paid
50 complaints mention a recall and 11 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
66% of these complaints say the check engine light came on.
- Stalls or shuts off24%19 of 80 complaints
- Loses power or goes into limp mode16%13 of 80 complaints
- Rattles or knocks16%13 of 80 complaints
- Uses or leaks oil16%13 of 80 complaints
- Overheats15%12 of 80 complaints
- Shakes, runs rough or misfires9%7 of 80 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
P0300 4 P0455 3 P0303 2 P0302 2 P050A 2 P1326 2
Other codes named in the same Kia Soul complaints, and in how many.
Repair costs
- Catalytic converter replacement$2,4904 bills · middle bill
Repair bills owners named in these 80 complaints (4 in all). Owner reports, not a quote: costs vary by shop and region.
Kia Soul engine replacement cost
Recalls on these Kia Soul years
- Engine · 2021 · issued 2025
The piston oil rings may have been manufactured incorrectly, which can result in engine damage. NHTSA 25V099000 - Engine · 2020, 2021 · issued 2021
The piston oil rings may not have been properly heat-treated, which may result in engine damage. NHTSA 21V259000 - Engine · 2014, 2015 · issued 2020
An engine compartment fire can occur while driving. NHTSA 20V750000 - Engine · 2012, 2013, 2014, 2015, 2016 · issued 2019
High exhaust gas temperatures may damage the catalytic converter, possibly resulting in abnormal engine combustion and damage to one or more of the engine's pistons and possible piston connecting rod failure. NHTSA 19V120000
4 recalls for the same systems (engine) on the Kia Soul 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
- Kia Soul reliability by year
- 2015 Kia Soul problems and recalls
Other codes Kia Soul owners report
P1326 P050A P0014 P0300 P0303 P0017 P0302 P1327
P0420 on other cars
Nissan Altima (19) · Ford Focus (16) · Hyundai Tucson (12) · Honda Odyssey (11) · 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): 11777428, 11776264, 11769993, 11769689, 11768690, 11768610, 11764798, 11762208, 11758898, 11757104, 11756561, 11753054 and 68 more.
Quick answers
What does P0420 mean on a Kia Soul?
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 Kia Soul years have the most P0420 complaints?
In complaints to NHTSA, owners of the 2015 (20), 2016 (16), 2014 (14) Kia Soul named P0420 most (80 complaints in all, 2012–2021). Raw counts, not a failure rate.
What fixes P0420 on a Kia Soul?
Owners most often name the catalytic converter (46 of 80 complaints), then engine software (a reflash) and pistons, rings or valves. That's what owners wrote, not a diagnosis: have a shop confirm the cause with a scan and tests before replacing parts.
At what mileage does P0420 show up on a Kia Soul?
Owners who gave their mileage reported a middle of 119,000 miles; half were between 89,000 and 145,000 (29 owners).
Can I drive my Kia Soul 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 Kia Soul, 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.