2019–2025 Mercedes-Benz B-Class · common problems & known faults

Dual clutch judder in slow traffic

Typically appears

60,000+ miles

What to inspect

Pull away from cold repeatedly

MBUX screen freezes and reboots

Typically appears

Age-related

What to inspect

Cycle every screen and voice function

Bush wear on larger wheel options

Typically appears

60,000+ miles

What to inspect

Listen for knocks over rough roads

Rear disc corrosion on low mileage cars

Typically appears

Age-related

What to inspect

Inspect rear discs for pitting

Coolant loss and sweet smell under the bonnet

Typically appears

40,000-60,000 miles

What to inspect

Shine a torch down the right side of the engine block (gearbox side) on 1.3L M282 engines. Look for pink or red crusty residue indicating a leaking plastic thermostat housing.

Engine management light and non-start countdown

Typically appears

30,000-50,000 miles

What to inspect

Turn the ignition on and scroll through the instrument cluster messages. Look for 'Refill AdBlue' warnings or a mileage countdown, which often indicates crystallized AdBlue injectors rather than an empty tank.

Grinding noise or binding from panoramic sunroof

Typically appears

3-5 years

What to inspect

Operate the sunroof switch to fully open and close the glass. Listen for crunching noises and visually inspect the exposed guide rails for dry, scored metal or snapped plastic wind deflectors.

Active Brake Assist functions limited warning

Typically appears

4-6 years

What to inspect

Start the engine and check the dash for collision prevention warnings. Inspect the flat Mercedes star badge on the front grille for water condensation behind the plastic or heavy stone chips disrupting the radar.