I’ve been having issues with the coolant in my Mazda 3 sport (2015). It recently came up with an orange warning triangle and said “vehicle system malfunction”. When I looked all of the coolant was gone from the tank, since then my heating will only blow cool air unless i’m driving. The garage I took it to couldn’t access the fault code so told me to go to a Mazda garage. They wiped the code so it couldnt be accessed and said to drive around to see if the warning light is triggered again, which it did 2 weeks later ( orange light and all the coolant gone).

I’m just wondering if the car needs to go to a mazda garage specifically as the last was unable to access the fault code?