Honda bulletin A26-009
What it saysUnder certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, and/or misfire. NHTSA’s full summary ↓
Honda filed this with NHTSA as a service bulletin dated Sep 25, 2026, received Aug 27, 2026, about the engine — 2 documents under this number. It names 6 model years (2016–2021). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
Get the next Honda Civic bulletin by email Weekly, only when something new is filed. Nothing else; one-click unsubscribe.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationService 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).
Trouble codes it names: P0300 P0304
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| A26-009 | Service bulletin | Sep 25, 2026 | 11037695 | PDF, 6,557 KB |
| A26-009 | Service bulletin | Aug 26, 2026 | 11036408 | PDF, 6,748 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themA vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
Email me new Honda bulletins for the Civic
A weekly email, sent only in a week when Honda files something new with NHTSA for the model you pick — service bulletins, campaigns, warranty extensions, over-the-air notices, every model year. Nothing else is sent; one-click unsubscribe in every message. Separate from recall alerts.
What owners reported
Source: NHTSA complaint databaseOwners of the 6 model years this bulletin names have filed 3,316 complaints with NHTSA since 2015. 265 of them name Engine — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
On the 2016 Honda Civic, the 54 owners who gave an odometer reading for Engine reported it at a median of 32,800 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
It is a common issue on the Honda Civic Type R from 2017 to 2021 in which water will leak through the hood scoop causing water to drip onto cylinder 4 causing a misfire. Misfire No. 4 Cylinder (DTC P0304). There is a TSB for it under 25-062 for this same issue. Water could enter the hood scoop and accumulate down inside the no.
2018 Honda Civic · Engine · filed with NHTSA May 28, 2026 · ODI 11740562
I recently discovered that coolant has been leaking into two of my cylinders, causing an overheating issue. The Honda dealership tells me this is a known issue for their engines for that year range, so much so that an extended warranty has been added to all other engines but there is a carve out for the Type-R.
2021 Honda Civic · Engine · filed with NHTSA Oct 28, 2026 · ODI 11774237
I leased a brand new 2016 Honda Civic on friday, february 26, 2016 and drove off the lot with 5 miles on the odometer. On monday, february 29, 2016, my car started to shake, the engine light came on as well as other indicators on the car, I was not able to accelerate or properly operate the vehicle.
2016 Honda Civic · Engine · filed with NHTSA Mar 1, 2016 · ODI 10839167
In depth: 2018 Honda Civic engine problems → · 2017 Honda Civic engine problems → · 2016 Honda Civic engine problems →
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the engine
Source: same model, same component group49 other manufacturer communications filed against the Honda Civic under the same component group (engine), newest first. The eight newest are listed; the rest are on the Honda list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| A26-099 | Service bulletin | Sep 25, 2026 | Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience ov… |
| A26-097 | Service bulletin | Sep 25, 2026 | Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience ov… |
| A26-013 | Service bulletin | Sep 25, 2026 | Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience ov… |
| A26-012 | Service bulletin | Sep 25, 2026 | Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience ov… |
| A26-011 | Service bulletin | Sep 25, 2026 | Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience ov… |
| A26-010 | Service bulletin | Sep 25, 2026 | Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience ov… |
| A26-008 | Service bulletin | Sep 25, 2026 | Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience ov… |
| AEBM08262026901 | Other | Aug 26, 2026 | Dealer Message - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience over… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Honda, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Honda A26-009 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the A26-009 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every Honda warranty extension on file lists the ones Honda has filed.
Which vehicles does A26-009 cover?
The manufacturer filed it against 6 model years: 2021 Honda Civic, 2020 Honda Civic, 2019 Honda Civic, 2018 Honda Civic, 2017 Honda Civic, 2016 Honda Civic. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.