P0304 on Hyundai vehicles Cylinder 4 is misfiring
P0304 is named on 12 Hyundai model years (2016–2025): 5 manufacturer filings and 11 owner reports in NHTSA’s files, across Accent, Elantra, Santa Fe, Santa Cruz, Sonata and 1 more.
Which Hyundai model years name P0304
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2019 Hyundai Elantra | Electrical System | 1 | 1 |
| 2018 Hyundai Accent | Engine | 2 | — |
| 2018 Hyundai Santa Fe | Engine | — | 2 |
| 2017 Hyundai Elantra | Equipment | 1 | 1 |
| 2025 Hyundai Santa Fe | Power Train | — | 1 |
| 2022 Hyundai Santa Cruz | Power Train | — | 1 |
| 2022 Hyundai Tucson | Fuel/Propulsion System | — | 1 |
| 2018 Hyundai Elantra | Electrical System | 1 | — |
| 2018 Hyundai Sonata | Engine | — | 1 |
| 2018 Hyundai Tucson | Engine | — | 1 |
| 2017 Hyundai Tucson | Engine | — | 1 |
| 2016 Hyundai Tucson | Engine | — | 1 |
A model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.
Hyundai filings that name P0304
Source: NHTSA manufacturer communicationsBulletins and campaigns Hyundai filed with NHTSA whose summary names P0304. Quote the document number at the service desk — it is a diagnosis the maker has already written down.
- 5NP-W7U4F-05 Service bulletin2018-04-25 · Engine And Engine Cooling
- This bulletin provides the procedure to inspect the current spark plugs, replace all 4 spark plugs, check new spark plug gap, and clear Diagnostic Trouble Codes (DTC). This bulletin addresses the following conditions: ? DTC P0300 / P0301 / P0302 / P0303 / P0304 Random/Multiple Misfire. ? Engine runs rough.
- 5NP-B4B6V-06 Service bulletin2018-05-22 · Electrical System
- This bulletin provides the procedure to inspect the current spark plugs, replace all 4 spark plugs, check new spark plug gap, and clear Diagnostic Trouble Codes (DTC). This bulletin addresses the following conditions: ? DTC P0300 / P0301 / P0302 / P0303 / P0304 Random/Multiple Misfire. ? Engine runs rough.
- 20-01-008H Service bulletin2020-02-13 · Electrical System — Software
- This bulletin provides information related to the Engine Control Module (ECM) software update for 2018 - 2019MY Elantra (AD/ADA) vehicles equipped with 2.0L engine. This software update includes cylinder imbalance learning logic optimization for Malfunction Indicator Light illumination with DTC P0300/P0301/P0302/P0303/P0304 (Cylinder “X” – misfire detected).
- 20-FL-001H Service bulletin2020-02-13 · Equipment
- Some 2017MY Elantra (AD/ADA) vehicles equipped with 2.0L engine may experience Malfunction Indicator Light illumination with DTC P0300/P0301/P0302/P0303/P0304 (Cylinder “X” – misfire detected). The bulletin provides information on the repair procedure.
What P0304 means
Source: SAE J2012 / OBD-IICylinder 4 is misfiring.
A stored code names the test that failed, never the part that caused it. The record above is what Hyundai and its owners have filed about it; the code’s page across every make has the whole file.
Common questions
Source: NHTSA files and the OBD-II standardIs P0304 a known problem on Hyundai vehicles?
It is a documented one: NHTSA's files hold 5 manufacturer filings and 11 owner reports naming P0304 on 12 Hyundai model years (2016–2025). Whether it is a problem on one particular car is a diagnosis, not a count — but a bulletin that names the code on your model year is the place to start.
Which Hyundai models does P0304 appear on most?
2018 Accent (2 documents), 2019 Elantra (2 documents), 2017 Elantra (2 documents).
Does P0304 on a Hyundai mean it is recalled?
No. Recalls are filed by campaign and matched by VIN; no recall is triggered by a scan tool. Check the VIN at nhtsa.gov/recalls, or open the model year's page here for the campaigns filed against it.