shalfira fira

Hello guys, my car always jerking every first 20 km/h only.. after i start the car and there are warnings pop-up says "1. Release parking break & 2. Front right/left malfunction, Consult workshop" After that it ran smoothly but sometimes the check engine warning light up but sometimes its gone automatically. So i went to workshop to diagnose, the fault code was P250513 (The power supply at the input of the control unit "combustion engine" has an electrical fault. There is an open circuit) but i don't know what exactly do i have to do with it. Several months after, i went to local mercedes agent to check.. but they update my software instead without my consent which got nothing to do with the car. The second time they check, they said its the backup battery relay (A0009822023).. is it really the relay or what.. and where can i find the new one online *cheap* ?

problem solved