Honda Civic 2016–2021 — technical service bulletin

Bulletin A26-009 · NHTSA communication 11036408 · issued Aug 26, 2026

Technical service bulletin

communication type

Engine

component

2016–2021

model years

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, misfire and/or DTCs P0300 thru P0304 stored.

Vehicles covered

2016 Honda Civic
2017 Honda Civic
2018 Honda Civic
2019 Honda Civic
2020 Honda Civic
2021 Honda Civic
2017 Honda Civic SI
2018 Honda Civic SI
2019 Honda Civic SI
2020 Honda Civic SI

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.