Where is a 2004 peugeot 206cc impact sensor located

It sounds like it could be a seat belt sensor. These only work when the car is moving. Do you have anything on the passenger seat that could make the car think there is a passenger there?
Try fastening all the seatbelts and see if the beeping continues. If there is no beeping, try unfastening the seatbelts one by one & see if you can find which one is causing the problem.
if it turns out it is a seatbelt sensor, you could drive with that belt fastened until you can get the sensor replaced.

There is a chip in the key fob, might need reprogramming by Peugeot! Try your spare key.

Probably the speed sensor, they tend to die.

PEUGEOT 306 206 98 SPEED SENSOR RPM GAUGE 616070 Speedometers CITROEN 3...

Have you tried to disconnect battery terminal and wait for 5 minutes before connecting again to check the remote locking?

tis on the nsf in the very corner.

I would say it's a bad ABS sensor. That's where I'd start looking.

Where is the esp sensor located in a Peugeot 206cc?

check the oil level, if this is ok you may need to replace the switch at the bottom of the oil filter housing

if this helps please let me know
cheers
big mike

As far as I know all the 206 mount the same internal mirror.

If instead you are talking about the driverside mirror, there that may be differences.

A good way to find out is going to a local Peugeot car parts dealer and asking their opinion.

Does not have a drip stick I think, my 206cc Auto does not have one either, it has a check level/drain plug !