R Atkin

January 2017. I am second owner of a Lincoln MKS 2011. Occasionally I was getting a NO KEY DETECTED ( about once a month for 6 months) , but this morning it was permanent after the vehicle had been sitting for a week . I carry the second IA in the trunk wrapped in foil, so tried that and it did not work either. The door Keyless access works for doors and trunk, and the door rocker switch to lock and unlock works.. Per Owners Manual BJ5 19A321 AA page219 for the car, the Back Up slot is located on the inside right side of the Glove box. Both IAs worked in that slot. The batteries in both IAs had been replaced in Oct 2016 and tested 'good' today. New CR 2032 batteries in the IAs did not fix the problem. The battery contacts in the IAs were carefully cleaned, and the batteries themselves cleaned, especially the outdide edge where the +ve contact is made in the IA. Cleaning was done using a barely moist cloth, and wiped with a dry cloth. Check that there is no fluff. Both IAs work now. Try not to touch the cleaned areas with bare fingers when installing batteries. I thought I would post this in case anyone has a similar problem. In past experience, I've found that some alkaline batteries and contact areas in TV remotes and clocks etc simply need to have the contact areas cleaned periodically. Hope this helped. I've posted here cuz my browswer only brought up 'Edge' altho I asked for MKS, but the entry systems sound similar.