Service bulletins for the 2021 Honda Civic
A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.
79 on file from NHTSA, as of 2026-10-19.
About P0300 on the 2021 Honda Civic: what the code means, and the bulletins and recalls about the same components.
By type
By component
By trouble code
Only bulletins with trouble code: P0300 are shown. Show all
| A26-009 | 2026-10-01. Service bulletin. ENGINE. 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). |
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| A26-008 | 2026-10-01. Service bulletin. ENGINE. 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). |
| AEBM08262026901 | 2026-08-27. Other. ENGINE. 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. |
| A26-009 | 2026-08-27. Service bulletin. ENGINE. 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. |
| A26-008 | 2026-08-27. Service bulletin. ENGINE. 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. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.