This bulletin applies to 2013-2016 Honda Accord vehicles. When driving under steady cruise between 30 and 65 mph or during light acceleration, if the engine intermittently rattles or runs rough with the MIL blinking, the probable reason is sticking VCM (Variable Cylinder Management) rocker arms, since these conditions are likely to activate VCM operation.
If the engine rattles going into VCM, this noise can be quite noticeable. You’ll hear the VCM rocker arm pin tapping against the other rocker arm as it tries to lock the two arms together going into valve pause. The VCM rocker arm can also stick in its locked position, causing both rocker arms to stay connected. When this happens, the engine intermittently runs rough and the MIL blinks.
If the engine is shut off and then restarted when these symptoms happen, the rocker arms may unstick, allowing normal operation with no misfire DTCs being set, which can make this problem tough to troubleshoot. Be sure to check out the Variable Cylinder Management Rocker Arm test in the service manual. Replacing the affected rocker arms usually fixes the problem.