Honda Civic 2016–2021 — technical service bulletin
Bulletin A26-009 · NHTSA communication 11037695 · issued Sep 25, 2026
Technical service bulletin
communication type
Engine
component
2016–2021
model years
10
vehicle entries
Official summary
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).
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.