I would buy and throw some 'Lucas Upper Cylinder Lubricant'.  I've used it in my Fords (from the Focus ZTW to my Ford C-Maxs) to avoid check engine codes. Cheap and doesn't hurt anything so why not try? 

I don't know.   The rule I've always followed was that vehicles manufactured on or after Aug. 15th 2015 had the 'fixed' transmission.  All those before that date were potential issues. 

Two C-Max owner here ('16' - built in Oct. 2015 and a '17') - you will get lower MPGs on the highway with a C-Max. Why?  Higher speed, using the AC. etc. I find I'm around 41-42 mpg on long highway drives (e.g. 6-11 hours). You're going faster, with AC and less battery time.  

You can get better MPGs by slowing down (60-65 mph vs 70-75 mph) but a longer time driving so I do 75 mph a lot.  I visit my B-I-L and do the trip (695 miles) in a one 11-11:30 hours day. I fill up at 500 miles since there are few (and expensive) gas stations near his house so it's better to tank up sooner rather than later. 

I run my Michelins (Energy Savers) at 50 mph and flip the AC on and off depending on hills (flip off the AC on uphills). 

On my '17' you can't run the fan only; it will kick on the AC no matter what.  You can on the '16' - wish they'd left it that way.

I don't coast downhills; prefer to slightly increase MPH downhill for a better run uphill (NYS Thruway).

Gas pods are a gimmick; worthless. I do let the battery re-charge on long downhills - amazing how fast you can go and recharge at the same time! I sometimes drive barefoot to get the best 'light touch' on the gas pedal. 

Find a good Ford dealership (look on line in Yelp, etc.) and get them to sort out the issues.  A 'local repair shop' doesn't have the access to all the technical stuff; just whatever rumor their local mechanic might have heard, somewhere.  

You could try some Lucas fuel injector cleaner.  I used to have carbon build up in the throttle body of my 2004 Ford Focus Wagon and Lucas would generally clear it out.  I now put it in our two C-Maxs (2016 & 2017) twice a year.  

Worth a try, cheap and it might buy you some time.

I bought a backup camera for my wife's 2016 from Costco ($122). A 'Type S'. Been a couple of years and it's been great. Wireless and solar powered. 

It was the second one I bought from Costco - the first one I discovered blocked the rear door handle so I returned it.  Then Costco started selling one with the camera off to the side so the handle was clear to use. 

Just checked Costco and all the back up cameras say 'Unavailable', so...

'Is that typical police cars?'   Can't answer that one.

But C-Max mileage goes down in the winter.  Why?  Because heating the car can't be done well with a battery so the C-Max fires up the engine to give you heat. I keep my car cold (my wife gets irritated) and my mileage is substantially better than my wife's (we both have C-Maxs). 

The less you run the AC or the heat the better your mpgs.  And using the terrain (letting off on the gas when going downhill and building up speed before uphills). 

Yes, you can own a '2016' that was built in 2015.  That was the case with my '2016' (I didn't know you could easily check the build date on the inside of the driver's door hinge then).

Fortunately, the important date is Aug. 15, 2015 ) 'on or before Aug. 15, 2015' means risk of transmission failure.  Our '2016 was built in Oct. of 2015 so it's 'safe'. 

Have 2 C-Maxs (one a '2016' but built in 2015).  Zero brake problems. 

Something is weird here and perhaps you need to go to a different dealer, etc.  Do you drive it differently?  

Most people with C-Maxs go 100k without any brake issues or needed repairs/maintenance. 

The 2017 year model is about the most reliable one according to Consumer Reports.  We have a 2016 (that we bought in 2018 with 2,700 miles on it) and a 2017 that we bought in 2020 with 16,600 miles on it - for $14,450). Great cars. 

Two C-Maxs, 2 physical keys each.  I didn't know people only had Fobs only.  Neither of our cars (SE models) have a push button starter; you have to put the metal key in the ignition and you can always open the driver's door with the physical key. 

If you max out the lumbar support it just does that.  Have you tried cycle in both ways?  That should tell you if it's broken or just maxed out.

Whenever you start to experience weird electronic issues (remote stops working, some electronic features seem disabled, etc.) it can be a sign that the battery is going.  I replace our (2 C-Maxs) at 5 years even if there haven't been issues.  Just not worth trying to 'stretch' battery life and ending up with a dead car in the wrong place at the wrong time. 
 

My dealer charged me $130 installed and it was a good deal. I mark the date of the new battery in my glove compartment book so I know and I put a reminder in our electronic calendar when replacement is due. 

When I first bought my C-Max I read some reviews on-line and one of them described the turning radius of the C-Max as: 'having the turning radius of a small moving van'.   Accurate. 

I know it's that way and now I just drive accordingly and expect lots of 3 point turns, turning into 6 points...

$130 from my Ford dealer - battery and installation.  I thought it was a good deal.  I bought two used C-Maxs (one in 2018 - a 2016 - and one in 2020 - a 2017) and replaced the batteries after purchase just to have a 'clean slate' and know the age of the battery.  My plan is to replace them after 5 years.  I know they can last longer but I'd prefer 'safe over sorry' since I've had batteries quite a the most opportune times in the past. 

Pretty much my experience with Ford support - I had a '2016' CMax SE' and they said I could upgrade it to Sync 3. On this forum it became clear that if you had the SE 'small screen' and my manufacture date of Aug. 2015 totally precluded any upgrade possibility.  I downloaded the files from Ford and couldn't even get them to work after hours of trying after encouragement from Ford.  

The Ford people knew far less than the average forum reader here! 

My 2004 Ford Focus ZTW wagon was really happy on Mobil One 0W-20 - noticeable difference and our now 2 CMaxs are happy with Mobil One as well. The dealer lets me bring Mobil One from Costco so I'm pleased with that approach since it saves a ton of money over either Mobil One dealer supplied or the Ford Synthetic.

Worth a try - the Lucas stuff is way cheaper than anything else.  If it doesn't work, or isn't a permanent solution you've lost nothing. 

Some dealers are better than others.  I have 3-4 dealers to choose from and have found a couple are much better than the others - more skilled, more honest.  One - the largest - has fixed stuff other dealers couldn't and for way less.  In fact, and it astonishes me...., this dealer will allow me to bring Costco purchased Mobil One oil with me and do the oil changes with it. They also fixed two items after fighting with Ford to get them covered!  Another time they screwed up on the time the car would be ready and filled up my gas tank for me - 13 gallons!

I agree with you on the infotainment being such a big factor but for some people it is huge (not me).   I'd stay with C-Maxs built after Aug. 15, 2015 to avoid transmission failure (at 100k plus). 

We have a '16' (manufactured in Oct. of 2015...) and a '17 (manufactured in Oct. of 2017) and the 2017 is by far the better of the two. Paid $14,450 for my 2017 SE with 16,400 miles. Zero issues with either so far. 

Take it to a dealer, man...

Could be rust on the brakes since they don't get used much (regenerative braking doing it instead).  I tend to hear it after the car has gotten wet and been sitting for a while as well. 

We have 2 CMaxs (2016 & a 2017, both bought used in 2018 and 2020) and they both make a scrapping sound when moving slowly with the windows open.  I tend to view anything both cars do as 'normal' and don't worry about it. 

A Diesel CMax?  What country are you in?  There are no diesel CMaxs in the US.  Are you in the UK?

My Ford dealer is quite lenient about owners being able to supply oil, filters and parts (I bring my own Mobil One that they allow since Costco beats their 'in house' cost by a huge margin) but they do say if you supply the parts they don't warranty them as opposed to their Ford parts.  You might want to keep that in mind if you're not doing the install yourself.