P0300 on Subaru vehicles Misfire detected, but not isolated to one cylinder
P0300 is named on 8 Subaru model years (2016–2020): 10 manufacturer filings and 1 owner report in NHTSA’s files, across Forester, BRZ, Impreza, WRX.
Which Subaru model years name P0300
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2016 Subaru Forester | Electrical System | 4 | — |
| 2020 Subaru BRZ | Electrical System | 1 | — |
| 2019 Subaru BRZ | Electrical System | 1 | — |
| 2018 Subaru BRZ | Electrical System | 1 | — |
| 2018 Subaru Impreza | Service Brakes | — | 1 |
| 2018 Subaru WRX | Equipment | 1 | — |
| 2017 Subaru BRZ | Electrical System | 1 | — |
| 2017 Subaru WRX | 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.
Subaru filings that name P0300
Source: NHTSA manufacturer communicationsBulletins and campaigns Subaru filed with NHTSA whose summary names P0300. Quote the document number at the service desk — it is a diagnosis the maker has already written down.
- 07-112-16R Service bulletin2017-08-08 · Electrical System — Alternator/Generator/Regulator
- 2.5L MODELS ONLY. This bulletin provides a procedure for diagnosis and repair of DTC P0300 which may result from fluctuation of the alternator's current output outside of the specified limits.
- 07-112-16R Service bulletin2016-11-08 · Electrical System
- New Alternator Assembly. This bulletin provides a procedure for diagnosis and repair of DTC P0300 which may result from fluctuation of the alternator?s current output outside of the specified limits.
- 711216 Service bulletin2016-08-12 · Electrical System — Alternator/Generator/Regulator
- This bulletin provides a procedure for diagnosis and repair of DTC P0300 which may result from fluctuation of the alternator?s current output outside of the specified limits.
- 11-193-19 Service bulletin2019-11-08 · Electrical System
- This bulletin announces availability of reprogramming files to optimize the Engine Control Module (ECM). These new files will stabilize engine RPM and combustion during warm-up due to slight differences in the air-fuel ratio between cylinders causing DTC P0300 to set.
- 11-188-19 Service bulletin2019-01-11 · Equipment
- This bulletin announces availability of reprogramming files to optimize the ECM on the STI models listed with EJ2.5 engine and manual transmission. These files enhance engine misfire diagnosis to reduce the possibility of an incorrect detection of DTC P0300: RANDOM / MULTIPLE CYLINDER MISFIRE DETECTED. The DTC may set during frequent accelerator pedal on and off at highway speed.
What P0300 means
Source: SAE J2012 / OBD-IIMisfire detected, but not isolated to one cylinder.
A stored code names the test that failed, never the part that caused it. The record above is what Subaru 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 P0300 a known problem on Subaru vehicles?
It is a documented one: NHTSA's files hold 10 manufacturer filings and 1 owner report naming P0300 on 8 Subaru model years (2016–2020). 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 Subaru models does P0300 appear on most?
2016 Forester (4 documents), 2020 BRZ (1 document), 2019 BRZ (1 document).
Does P0300 on a Subaru 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.