Hello, I'm a new member and decided to jump into this old thread. This year, I bought a new 2014 C-Max Hybrid SEL with 240 miles. Now, it has just over 4,000 mi. I am experiencing an issue with the Active Noise Control (ANC).
My ANC does not like passengers in the front seat for the most part. It's my daily driver and only when family of lunch buddies get in the car, the low db noise happens. Quite painful to everyone's ears and very embarrassing. Some of my passengers even put their fingers into their ears and say, "...make it stop.". At first, it does sound like the engine at low rpm, but you can easily prove, that it is the ANC. When it happens, just reach up and start tapping one of the over head microphones. The front passenger microphone works the best. If you hold the throttle steady when the drone is heard, start tapping the mic, and the noise goes away. Quit tapping, it immediately comes back. The front driver's mic has to be tapped slightly harder, and the rear mic even harder. The focus appears to be on the front passenger area. As tapping is awkward, especially when looking forward while driving and feeling the ceiling for the mic, I choose to increase/decrease the throttle. The only times by myself, that I can hear the db noise start, but never reach the full drone stage, is in music on Sirius XM radio. It will sound as if you set a sub woofer to low in the db, then it begins to distort the song. I listen to 80s, Message, and Boneyard. It's the base guitar/keyboard, that brings it out.
I've taken it to the Ford dealer twice, drove the car with serviceman inside, but cannot seem to duplicate the problem. Once in the early morning on a cool day around 68 degrees, and another on a hot day over 80 degrees around lunch time. You do not have to drive the car long to hear it. About a 1/2 mile, but I cannot get anyone from Ford with me to hear it, nor do I. I've even had my lunch buddies turn off their iPhones and think happy thoughts. I cannot even record the sound with the iPhone. You can hear my buddies and I complain, that we're hearing it, but during playback, it's not there. The iPhone must be compensating it.
I'm going to take some vacation days off this November, and let them look at the car. I did notice that the ceiling is quite peculiar. I bought a sun visor the other day, one of the ones with two screens you fold into a circle, and its tends to open and go into the open cavity above the ceiling. If you feel the front edge of the ceiling with your hand, you can put all fingers above the ceiling and you feel the back side. The fabric just ends at the cut edge with no molding to protect it. It's bare and you can feel the foam that it is adhered too along its edge. I read about the ceiling recall done at the factory to add more impact material during the crash. If you look around the car, you can see where the fabric doesn't sit quite well on the pillar moldings and weather stripping. On the right rear passenger pillar molding, the fabric shows a stain of orange, that reminds me of the old days of using contact cement for replacing window channels on my old Fords. Unscrew the top, use the applicator brush, and whoops too generous with the cement.
Other than the ANC. It's been a good car. I'm getting about 47 mpg.