Two problems related to gas recirculation valve (egr valve) have been reported for the 2018 Honda Accord. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2018 Honda Accord based on all problems reported for the 2018 Accord.
Loud humming/whining noise occurs while driving at speeds between 35-50 mph. The only way to stop this ear splitting noise is to crack a window. According to the dealer, it is a known-issue with the automatic noise cancelling system in 2018 Honda Accords and later. Honda hasn't been able to fix this issue in over 3 years. It is extremely distracting to the driver, not to mention unsafe to have to drive with the window open in freezing temperature and rain. It happens to me almost every time I drive, especially in temperatures below 50 degrees.
Driving southbound on 101 south on sunny clear day 65 degrees with almost full fuel tank and 2 battery bars (almost empty) and climbing up incline on 7 degree grade and check engine light went on and lost all power and car completely slowed down to a stop (luckily was able to pull over with no problem).