Calif

That's the same problem I have. (except for me, it's both the front and rear Parking Aid that quit sounding, but rear cross-traffic alerts still sound). Also, no problem with the BLIS here on either side. The fact that you recently replaced your 12V battery and still have this problem seems to confirm a problem with the Park Aid "module", as I was told by the FORD dealership (I was hoping that replacing the battery could be an easy fix)

So I guess check the 12V battery after only 4 years is my best bet at this time? Thanks for the advice.

Actually, that's what I meant by "Also the Park Assist function now automatically turns off when I start the car." The button goes into Park Assit OFF mode when I start the car, and pressing it cannot turn it back ON.

I have a 2018 CMax Hybird Titanium. After picking it up from a regular service (oil change / tire rotation), I noticed the front/rear proximity sensors stopped working (i.e. not beeping anymore when getting close to an obstacle). Also the Park Assist function (that I never used) now automatically turns off when I start the car. However, the rear cross-traffic sensors are still OK (i.e. still beeping if a car comes from the left or right when I'm in reverse). The Fors dealer where it was serviced says it cannot be related to the regular service they just performed, and that it's probably the "module" that needs to be replaced (~$1000!), but they want to charge me $169 just to check it first. (of course, that car is 4-years old, and out of warranty for the safety/tech features, apparently). Is there anything else I can check before going that route? Any suggestion? Thanks!