Originally Posted by BAL278
They are reset on start up.
Also.. when you hit the button once, I believe it disable DSC and activates DTC.. if you press and hold the button it disables both and displays a traction symbol
When you hit the button DTC the DSC enters DTC mode, a version of the DSC. When you hold it for 3 seconds, DSC is turned but ABS, ABD, etc are left on.
EDIT: DTC replaces DSC when activated.
EDIT 2: I was correct originally, DTC is a mode of DSC.