P0304 on Alfa Romeo vehicles Cylinder 4 is misfiring
P0304 is named on 9 Alfa Romeo model years (2017–2022): 14 manufacturer filings and 0 owner reports in NHTSA’s files, across Giulia, Stelvio.
Which Alfa Romeo model years name P0304
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2019 Alfa Romeo Giulia | Electrical System | 2 | — |
| 2019 Alfa Romeo Stelvio | Electrical System | 2 | — |
| 2018 Alfa Romeo Giulia | Electrical System | 2 | — |
| 2018 Alfa Romeo Stelvio | Power Train | 2 | — |
| 2017 Alfa Romeo Giulia | Electrical System | 2 | — |
| 2022 Alfa Romeo Giulia | Electrical System | 1 | — |
| 2022 Alfa Romeo Stelvio | Electrical System | 1 | — |
| 2021 Alfa Romeo Giulia | Electrical System | 1 | — |
| 2021 Alfa Romeo Stelvio | Electrical System | 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.
Alfa Romeo filings that name P0304
Source: NHTSA manufacturer communicationsBulletins and campaigns Alfa Romeo 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.
- S2018000011 Service bulletin2020-10-27 · Electrical System
- Issue includes a fault code(s) set in the Powertrain Control Module (PCM) for P0299, P0300, P0301, P0302, P0303, and/or P0304 after performing the PCM software update process for Customer Satisfaction Notification (CSN) W05.
- S2018000011 Service bulletin2020-10-27 · Electrical System
- Issue includes a fault code(s) set in the Powertrain Control Module (PCM) for P0299, P0300, P0301, P0302, P0303, and/or P0304 after performing the PCM software update process for Customer Satisfaction Notification (CSN) W05.
- 0900222 Service bulletin2022-01-25 · Electrical System
- Ignition Coil Double Wire Causing Misfire This bulletin involves replacing all four ignition coils. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find one or more of the following Diagnostic Trouble Codes (DTCs): P0301 - Cylinder 1 Misfire Detected. P0302 - Cylinder 2 Misfire Detected. P0303 - Cylinder 3 Misfire Detected.
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 Alfa Romeo 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 Alfa Romeo vehicles?
It is a documented one: NHTSA's files hold 14 manufacturer filings and 0 owner reports naming P0304 on 9 Alfa Romeo model years (2017–2022). 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 Alfa Romeo models does P0304 appear on most?
2019 Giulia (2 documents), 2018 Giulia (2 documents), 2017 Giulia (2 documents).
Does P0304 on a Alfa Romeo 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.