P0300 on the 2018 Mazda Mazda3
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
Nobody has written a description of this code yet.
| 01-007-19-3541 | 2019-02-19. Service bulletin. When the engine is started for the first time after parking the vehicle overnight in cold conditions (below 32 degrees Fahrenheit / 0 degrees Celsius), some vehicles may exhibit a rough idle and/or the check engine light on with any of the following DTC(s) stored in memory. P0300 - Random misfire detected P0301 - Cylinder No. 1 misfire detected P0302 - Cylinder No. 2 misfire detected P0303 - Cylinder No. 3 misfire detected P0304 - Cylinder No.4 misfire detected. This may be caused by frozen water accumulated in the main silencer, restricting exhaust flow. |
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| 01-006-18-3429 | 2018-04-23. Service bulletin. When the engine is started for the first time after parking the vehicle overnight in cold conditions (below 32 degrees Fahrenheit / 0 degrees Celsius), some vehicles may exhibit a rough idle and/or the check engine light on with any of the following DTC(s) stored in memory. P0300 - Random misfire detected P0301 - Cylinder No.1 misfire detected P0302 - Cylinder No.2 misfire detected P0303 - Cylinder No.3 misfire detected P0304 - Cylinder No.4 misfire detected. This may be caused by frozen water accumulated in the main silencer, restricting exhaust flow. |
2 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.