# Service bulletin A26\-005

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.

- Type: Service bulletin
- NHTSA id: 11037689
- Published by NHTSA: 2026\-10\-01
- Manufacturer's number: A26\-005
- Manufacturer's date: 2026\-09\-25
- NHTSA component: ENGINE

## NHTSA's 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 \(DTCs are not required for repair\).

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11037689-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11037689-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine

## Trouble codes named

P0300, P0304

## Vehicles listed

- 2023 to 2026 HONDA ACCORD

## Other bulletins for the same vehicles and component

- [A26\-007](/bulletins/11037691.md), 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](/bulletins/11036424.md), 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\-007](/bulletins/11036406.md), 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\-005](/bulletins/11036404.md), 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\-080](/bulletins/11035782.md), 2026-08-05, Service bulletin: ENGINE; FUEL/PROPULSION SYSTEM. Service Bulletin \- To better manage engine temperatures, a PGM\-FI update has been developed to optimize electric water pump operation.
- [AEBM07242026902](/bulletins/11035778.md), 2026-08-05, Other: ENGINE; FUEL/PROPULSION SYSTEM. Dealer Message \- To help improve engine temperatures, a software update has been developed for the electric water pump to optimize its operation.
- [A25\-017](/bulletins/11034202.md), 2026-07-01, Service bulletin: ENGINE. Service Bulletin \- A slight engine vibration and the Malfunction Indicator Lamp \(MIL\) is ON with DTC P0700 \(Transmission Control System MIL Request\) set during start\-up in below freezing temperatures.
- [A26\-025](/bulletins/11031499.md), 2026-04-22, Service bulletin: ENGINE. Service Bulletin \- The current Power Control Unit \(PCU\) Radiator Guard does not provide adequate protection. Roadway debris can cause damage to the PCU Radiator which may result in multiple warning lights, Malfunction Indicator Lights \(MIL\), and decreased hybrid system performance.
- [ATI\&03032026905](/bulletins/11030077.md), 2026-03-16, Other: ENGINE. Dealer Message \- American Honda Motor Co., Inc. \(AHM\) is searching for certain 2023\-2025 FHEV Accords \& CR\-Vs with a customer complaint of an oil leak or a dealer noticing an oil leak from the cylinder head cover gasket during routine maintenance. To better understand the cause of this condition, AHM would like to collect certain parts from the vehicle prior to you attempting a repair of any kind.
- [ATI\&10012025906](/bulletins/11024249.md), 2025-10-14, Other: ENGINE. Dealer Message \- American Honda Motor Co., Inc. \(AHM\) is searching for certain 2023\-2024 FHEV Accords \& CR\-Vs with a customer complaint of an oil leak or a dealer noticing an oil leak from the head cover gasket during routine maintenance. To better understand the cause of this condition, AHM would like to inspect the vehicle prior to you attempting a repair of any kind.

JSON: [/v1/bulletins/11037689](/v1/bulletins/11037689)

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