The stop button in case of impact is brought next to the right shock absorber turret, near the camshaft pulley cover, go to the chassis and is usually a two -centimeter square box by two with a red or black rubber button on the top.
If the button has jumped, just press it to rearm it again. If you have anything else, you will be scanning to see the breakdown codes and make a checkeo of pyrotechnic pretensioners and airbags (despite being an impact behind, sometimes the accelerometers or cables that pass below the seats) are marked.
All the best.