на панеле приборов во время движения загорелось bus esp .

А может, все же, BAS/ESP? у мерсов есть такой индикатор
имеет отношение к brake assist and electronic stability systems, то есть к системам электронной устойчивости и вспомогательного торможения
http://www.pro-motors.ru/termin-31.htm
как сказано в интернете, типичной причиной этого может быть и неисправный переключатель стоп сигнала или же датчик поворота руля. для более точной оценки техник должен считать код ошибки с бортового компьютера
http://www.justanswer.com/questions/1teqz-what-causes-my-bas-esp-light-to-come-on

The BAS/ESP lights pertain to your brake assist and electronic stability systems. One of the more common problems we find is a faulty stop light switch or a steering angle sensor. It would be a good idea to have the fault codes read. The codes would give you a pretty good idea as to what is going on. You could try to initialize the steering angle sensor first. This is normally needed after a dead or weak battery condition. To do this you'll need to start the car and then turn the wheel slowly all the way to the left, pause and then turn slowly all the way to the right, pause and return to center. You may need to do it a couple of times to initialize the sensor. The stop light switches are inexpensive ($20.00) and easily replaced. They're located under the dash at the brake pedal. When you get your new switch you'll see a little release tab on it. You just depress the tab and rotate the switch 90° to remove it. Of course you may have other problems. Reading the fault codes would be the best place to start. Let me know if you have any questions.