2008 Parking sensor sound

Greetings Friends. My vehicle is a 2013 model 2008 Allaure series vehicle. The front parking sensor of my vehicle shows distance on the screen, comes into play, but the warning system with sound does not work. There is no problem with the sensors on the back, there is a warning on the screen and an audible warning. I had a computerized fault finding process in the repair shop, no fault was detected. But we cannot solve the problem. I would be pleased if you have information or advice.

my teacher, the sound should be out of the normal reports, and it may be upheld with the sound settings. have your settings checked.