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P0300 on the 2018 Honda Civic

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.

Bulletins for this model year that name P0300
A26-0092026-10-01. Service bulletin. Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, and/or misfire. In some cases, DTCs P0300 through P0304 may also be stored (DTCs are not required for repair).
A26-0082026-10-01. Service bulletin. Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, and/or misfire. In some cases, DTCs P0300 through P0304 may also be stored (DTCs are not required for repair).
AEBM082620269012026-08-27. Other. Dealer Message - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, misfire, and/or DTCs P0300 through P0304 stored.
A26-0092026-08-27. Service bulletin. Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, misfire and/or DTCs P0300 thru P0304 stored.
A26-0082026-08-27. Service bulletin. Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, misfire and/or DTCs P0300 thru P0304 stored.
A19-0332023-01-20. Service bulletin. Service Bulletin - Under certain circumstances, the vehicle may experience driveability issues, which may result in DTCs P0300 (random misfire detected), P0301 (No. 1 cylinder misfire detected), P0302 (No. 2 cylinder misfire detected), P0303 (No. 3 cylinder misfire detected), P0304 (No. 4 cylinder misfire detected), or P0172 (fuel system too rich) or a whirling noise coming from the engine compartment.
A19-0122023-01-20. Service bulletin. Service Bulletin - This bulletin is replaced by S/B 19-033, Warranty Extension: 2016-18 Civic 1.5L: Software Update with A/C Control Unit Replacement; DTC P0300, P0301, P0302, P0303, P0304, or P0172; Whirling Noise from Engine.
A19-0382019-10-09. Service bulletin. Service Bulletin - Under certain circumstances, the vehicle may experience driveability issues, which may result in DTCs P0300 (random misfire detected), P0301 (No. 1 cylinder misfire detected), P0302 (No. 2 cylinder misfire detected), P0303 (No. 3 cylinder misfire detected), P0304 (No. 4 cylinder misfire detected), or P0172 (fuel system too rich) or a whirling noise coming from the engine compartment.
ONLE4C070820192019-07-23. Service bulletin. Owner Notification Letter - Some 2016-18 Civic vehicles equipped with the 1.5 liter turbocharged engine may experience driveability issues. This may result in Diagnostic Trouble Codes (DTCs) P0300 (random misfire detected), P0301 (No. 1 cylinder misfire detected), P0302 (No. 2 cylinder misfire detected), P0303 (No. 3 cylinder misfire detected), P0304 (No. 4 cylinder misfire detected), or P0172 (fuel system too rich) or a whirling noise coming from the engine compartment. These concerns may result in the Malfunction Indicator Lamp (MIL) turning on.
ONLD4D07082019_22019-07-23. Service bulletin. Owner Notification Letter - Some 2016-18 Civic vehicles equipped with the 1.5 liter turbocharged engine may experience driveability issues. This may result in Diagnostic Trouble Codes (DTCs) P0300 (random misfire detected), P0301 (No. 1 cylinder misfire detected), P0302 (No. 2 cylinder misfire detected), P0303 (No. 3 cylinder misfire detected), P0304 (No. 4 cylinder misfire detected), or P0172 (fuel system too rich) or a whirling noise coming from the engine compartment. These concerns may result in the Malfunction Indicator Lamp (MIL) turning on.

23 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.