Mercedes C-Class (W205/W206) 48V EQ Boost Battery Crash Data Reset

Specialist Postal Repair Service

Why Does My Mercedes C-Class (W205/W206) 48V Battery Lock After a Collision?

Modern Mercedes C-Class (W205/W206) models fitted with the EQ Boost mild-hybrid system store crash event data inside the 48V battery's Battery Management System (BMS) as a safety measure — even after minor collisions, or sometimes low-speed bumps that trigger the sensor. Once this crash flag is written, the 48V system locks out and cannot be re-armed by standard diagnostic tools, since the crash record is held in a protected memory area. This typically triggers fault codes such as B183319, B183349, B183371, B183387, disables mild-hybrid start-stop assistance, and can prevent a clean MOT pass.

Can the 48V Battery Be Reset Without Replacement?

Yes — in the large majority of cases, the 48V battery itself is undamaged; only the BMS crash flag needs to be professionally cleared. Replacing the entire 48V battery at a dealership can cost significantly more than a reset service, and is often unnecessary once the crash data has been properly addressed.

How It Works

1. 1 Purchase this listing
2. 2 Remove the 48V battery/BMS unit from your vehicle (message us if you need help locating it)
3. 3 Post it to our repair centre:
   The Vehicle Check Office 13, 25 Mollison Avenue
   Enfield, EN3 7NJ
4. 4 Our technicians diagnose, reset, and bench-test the unit
5. 5 Your unit is returned via tracked delivery

Mercedes and EQ Boost are used here for reference and compatibility purposes only; The Vehicle Check is an independent repair specialist and is not affiliated with Mercedes.