2015 C4GP B78 1.6 BlueHDI 120, Random Key not detected

[Jimbob 1972]

Hi All.
For a few months now, I get a random "Key not detected" warning. I've changed the battery in both fobs, the fobs open, lock, start, stop with no issue, but every now and then I get the warning. Car battery was changed earlier this year.
It happened tonight as I was dropping someone off. as soon as the passenger door shut, the warning came up. engine was running and everything working as it should.
Anyone got any ideas, or links to a prior post. I couldn't find anything like this except a for very repeated "change battery" posts.
Cheers.

[GiveMeABreak]

That has nothing to do with batteries. It means that with the Hands Free system, the vehicle is not detecting the fob within the defined proximities of the vehicle.

Example: This will happen if you leave the car idling, get out of the vehicle with the fob in your pocket and walk away from the vehicle a certain distance. The message and an alarm will flash on the dashboard saying it cannot detect the key.

It can be ignored for this sort of issue.

The vehicle has aerials at specific locations within the vehicle to detect the fob on hands free entry and starting enabled vehicles. It's what prevents you locking the car when you leave the hands free fob in the car and try to lock the doors by touching the handle sensors - it won't be permitted.

If the message is going off with the fob in the vehicle then you may have a faulty aerial or another issue with the hands free ECU. But this will need a diagnostic to determine with a professional level diagnostic tool (not a generic scanner).

[Jimbob 1972]

Thanks Marc. most helpfull.