My 2019 GLC is having two issues. On three occasions whilev going high speed on the freeway my car has slowed down to a stop. I pushed the call button and Mercedes told me to turn off the car, remove then reinstall the gas cap to start it. It worked. However the mechanics have been unable to diagnose the issue. On several occasions the check engine light went on. Mercedes told me to do the same and the check engine light will go off in 24-48 hours.