I am having problems with my new MKC with 'No Key Detected". It wont start right away and I have to wait 15-20 minutes. it has been in the shop twice and I was given new key Fobs. 3 days later the problem persist, of course not in the dealership! so my new car has been in the shop almost 2 weeks out of the 10 I owned it!
I had the same problem with my wife's 2014 MKZ and later with my 2015 MKC. I called the dealer and he said I may have a dead battery. Seems too soon for that and unusual that it hit two cars, and the problem later went away. Luckily when this did occur, each of our cars was in our garage at home - at least not in a shopping mall parking lot at night.
I have an electrical background, and find that many problems of battery operated devices (such as flashlights, etc.) are due to a bad connection between the battery terminals and the device. (Same thing happens if we have a loose battery cable). Anyhow, here is what I did for both of our cars, which so far seems to have solved the problem:
I disassembled the key fob (kind of tricky to get the second section that holds the batteries out). I first very slightly pulled up on the small flat spring tabs that touched the first battery so as to put just a little more pressure on these springs against the battery.
The batteries are separated by a white insulation telling "change both batteries or something like that". What I then did was take a 3"x3" Postit Note and cut off the top 3/4" (adhesive end of Postit). I then four-folded this together into a 3/4" x 3/4" square, and with a pair of scissors, cut this square folded part into a circle that is slightly smaller than the 3/4" diameter battery (cut to about 11/16" diameter). I then I inserted this section on top of the white insulation tab between the two batteries, so as to apply just a very little additional pressure between the top battery and the small flat spring tabs.
Reassembled the key fob, being careful to feel and hear both upper and lower sections click into the closed position. It seemed to fit tightly and was a little harder to get closed, which is good. So far, so good. I noticed that somewhere I read not to remove the grease on the battery, which I did not do.
How would you like to be a Service Manager and have this occur repeatedly with the same customer? Sometimes the simplest answer to a problem is not always replacement, but instead to use a little ingenuity.
P.S. My son and I have a 50-vehicle antique and classic car museum in Canfield, Ohio........ Home
....... We often discover little things to keep our cars in running condition and this does not always include "replacement".