Just replaced my PCM2.1 with an Alpine iLX-207 HU and the HUR NAV-TV210, 2008 997TT with the Bose Amp.
Now I have my seat-belt chime coming on at 76MPH and off at 71MPH WTH!!!
Anyone have any thoughts I have a Durametric Pro and went into the instrument cluster and turned all the chimes off.
Another interesting thing the car is equipped with the Sports Chrono it hasn't worked since i purchased the car in August 2018 not it does work.

 

You sure it's not the speed limit chime ? Does the dash display a fasten seat belt icon when the chime is happening?

 

Speed limit chime has a different sounds also alerts you in the multi function display. I unbuckled at 65MPH and the seat belt warning on the dash let's me know and same chime goes off.
Next test or step is to reinstall the PCM.

 

I pulled the Alpine and drove with the stock PCM then no PCM, no change. Must be a malfunction of some kind.
I also removed the factory XM, 6CD changer and NAV system don't think it has any affect as its fiber optic and power. Looped the Bose amp back in.

 

no seat belt icon I suspect this chime is used for other warnings like head lights on and key in ignition. Very Bizarre I will need to get some one with a piwis 2 or dealer to diagnose this live to figure out the trigger.

 

SOLVED!!
Reset the ECU and all good now.