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Service bulletins for the 2021 Honda Civic Type R

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.

16 on file from NHTSA, as of 2026-10-19.

About P0304 on the 2021 Honda Civic Type R: 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: P0304 are shown. Show all

Bulletins, newest first
A25-0622025-11-04. Service bulletin. ENGINE. Service Bulletin - Water could enter the hood scoop and accumulate down inside the no. 4 spark plug hole. This can corrode the ignition coil, plug tube, and spark plug, leading to a misfire to the no. 4 cylinder. If a misfire is detected, DTC P0304 is stored.
A25-0622025-08-21. Service bulletin. ENGINE. Service Bulletin - Water could enter the hood scoop and accumulate down inside the no. 4 spark plug hole. This can corrode the ignition coil, plug tube, and spark plug, leading to a misfire to the no. 4 cylinder. If a misfire is detected, DTC P0304 is stored.
ATI&091420239012023-09-21. Service bulletin. ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM. Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2017-2021 Civic Type R with a customer complaint of the vehicle Malfunction Indicator Light (MIL) with DTC P0300 (Random Misfire Detected) and/or P0304 (No. 4 Cylinder Misfire Detected) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.
ATI&082920239042023-09-06. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2017-2021 Civic Type R with a customer complaint of the vehicle Malfunction Indicator Light (MIL) with DTC P0300 (Random Misfire Detected) and/or P0304 (No. 4 Cylinder Misfire Detected) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.
ATI&081420239012023-08-18. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2017-2021 Civic Type R with a customer complaint of the vehicle Malfunction Indicator Light (MIL) with DTC P0300 (Random Misfire Detected) and/or P0304 (No. 4 Cylinder Misfire Detected) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.
ATI&072820239032023-08-03. Service bulletin. ENGINE AND ENGINE COOLING. Dealer Message -American Honda Motor Co., Inc. (AHM) is searching for certain 2017-2021 Civic Type R with a customer complaint of the vehicle Malfunction Indicator Light (MIL) with DTC P0300 (Random Misfire Detected) and/or P0304 (No. 4 Cylinder Misfire Detected) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.