The Lemon IndexCylinder 3 is not firing properly, so the engine runs rough and loses some power. Full P0303 page
14 owner complaints · the #6 code Kia Soul owners name · 7% of Kia Soul complaints that name a code (every car: 2.4%)
2012–2022 Kia Soul · most: 2021 (2), 2018 (2), 2016 (2)
Kia Soul owners named P0303 in 14 complaints to the U.S. government (NHTSA), most often on the 2021, 2018 and 2016 model years. The part they name most is the pistons, rings or valves (6 complaints). Complaints are owner reports, not proof of a defect.
Kia Soul model years that report P0303
Owner complaints naming P0303, 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 pistons, rings or valves, in 6 of the 14 complaints (43%). 1 of those mention it being replaced or repaired. Next: engine (replaced or rebuilt) (5), spark plugs (3) and ignition coils (2).
- Pistons, rings or valves6 complaints1 mentions a repair or replacement
- Engine replaced or rebuilt5 complaints4 mention a repair or replacement, 1 of them says the problem came back · what Kia Soul owners paid
- Spark plugs3 complaints2 mention a repair or replacement, 1 of them says the problem came back · what owners paid
- Ignition coils2 complaints2 mention a repair or replacement, 1 of them says the problem came back · what owners paid
7 complaints mention a recall and 4 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 P0303
43% of these complaints say the check engine light came on.
- Shakes, runs rough or misfires57%8 of 14 complaints
- Stalls or shuts off43%6 of 14 complaints
- Rattles or knocks36%5 of 14 complaints
- Uses or leaks oil36%5 of 14 complaints
- Loses power or goes into limp mode29%4 of 14 complaints
- Transmission slips or shifts hard14%2 of 14 complaints
Share of the complaints naming P0303 whose text also describes each problem. A complaint can describe more than one.
Codes owners report with it
P0300 10 P0302 6 P0014 3 P0301 3 P0304 3 P0017 3
Other codes named in the same Kia Soul complaints, and in how many.
Repair costs
Kia Soul engine replacement cost
Recalls on these Kia Soul years
- Engine · 2021, 2022 · 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 · issued 2020
An engine compartment fire can occur while driving. NHTSA 20V750000 - Engine · 2012, 2013, 2014, 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 P0303. Recall work is free at any dealer: check a VIN at nhtsa.gov/recalls or with our VIN check.
Keep going
- P0303: meaning, causes and every car that reports it
- Kia Soul reliability by year
- 2021 Kia Soul problems and recalls
Other codes Kia Soul owners report
P0420 P1326 P050A P0014 P0300 P0017 P0302 P1327
P0303 on other cars
Ford Escape (62) · Ford Edge (34) · Chrysler Pacifica (26) · Honda CR-V (23) · Ford Fusion (22) · Honda Accord (20) · Honda Odyssey (16)
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 P0303 means
Cylinder 3 is not firing properly, so the engine runs rough and loses some power. A flashing check engine light means the misfire is serious enough to damage the catalytic converter, so slow down and get it checked right away.
Get it fixed soon. A few more days of normal driving is usually OK, but waiting can turn a small repair into a bigger one or a breakdown.
- Spark plug or ignition coil on cylinder 3
- Fuel injector on cylinder 3
- Vacuum leak near that cylinder
- Low compression (valve or piston ring problem)
Check the complaints yourself
NHTSA complaint numbers (search them at nhtsa.gov): 11748114, 11736581, 11725093, 11720416, 11699918, 11697208, 11650213, 11645566, 11604037, 11579469, 11525628, 11452613 and 2 more.
Quick answers
What does P0303 mean on a Kia Soul?
Cylinder 3 Misfire Detected. Cylinder 3 is not firing properly, so the engine runs rough and loses some power. A flashing check engine light means the misfire is serious enough to damage the catalytic converter, so slow down and get it checked right away.
Which Kia Soul years have the most P0303 complaints?
In complaints to NHTSA, owners of the 2021 (2), 2018 (2), 2016 (2) Kia Soul named P0303 most (14 complaints in all, 2012–2022). Raw counts, not a failure rate.
What fixes P0303 on a Kia Soul?
Owners most often name the pistons, rings or valves (6 of 14 complaints), then engine (replaced or rebuilt) and spark plugs. 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 Kia Soul with P0303?
Get it fixed soon. A few more days of normal driving is usually OK, but waiting can turn a small repair into a bigger one or a breakdown.
Sources: NHTSA owner complaints that name P0303 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.