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P0304 on the 2020 Honda Civic Type R

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

Nobody has written a description of this code yet.

Bulletins for this model year that name P0304
A25-0622025-11-04. Service bulletin. 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. 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. 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. 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. 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. 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.

6 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.