Mercedes-Benz B 200
Development of the M166 with CVT option. Turbo variant (200 Turbo) powerful but rare. Solid everyday engines with few typical failures.
Base Engine
100 kW is enough in the compact for daily use. Nothing more, nothing less.
Engine Weaknesses 5
The Autotronic CVT (722.8) on the M266 is failure-prone: the push belt wears or the output speed sensor in the control unit fails. When faulty, only engine rpm rises on acceleration with no drive.
Symptoms: Engine revs climb, vehicle does not accelerate, CVT warning on display, no drive in D or R
The CVT gearbox control unit develops faults in the internal speed sensor. Typical fault codes are P0706 and 0722/0723. New control unit requires manufacturer programming and is expensive.
Symptoms: Fault message 'Transmission — visit workshop', jerky shifting, vehicle stranding, gearbox limp mode
The optional Autotronic CVT gearbox is considered the weak point of the W245. Typical faults: speed sensors, control unit, and premature push-belt wear. Repair costs frequently exceed the vehicle's value.
Symptoms: Judder when pulling away, unusual noises from gearbox, vehicle no longer shifts, gearbox stuck in one gear
The M266 uses one ignition coil for two cylinders (1/2 and 3/4). Faulty coils cause misfires that typically occur above approximately 2,800 rpm. CEL and limp mode follow.
Symptoms: Rough engine, stumbling above a certain rpm, CEL flashing or permanently lit, vehicle enters limp mode
The M266 is prone to oil loss at valve cover gasket and camshaft adjuster seals, like its predecessor the M166. At higher mileage a systematic inspection of all seals is necessary.
Symptoms: Oil spots under the vehicle, oil smell, visible oil traces on engine block, oil level drop
Vehicle Weaknesses 6
Early rust starts at door lower edges and spreads to bonnet and strut tops. Vehicles only 3 years old already show initial rust. Typical problem of early model years.
Driveshaft gaiters become leaky prematurely; without immediate repair the shafts break completely. MOT regularly flags driveshafts and steering joints. Replacement costs €430–650.
Vehicles before the 2008 facelift show pronounced corrosion on lower door edges, bonnet and strut tower mounts. Mercedes carried out goodwill repairs.
As with the related W169, A/C condensers lose refrigerant through defective solder joints. A/C fails at higher temperatures. Replacement requires engine bay disassembly.
Rear leaf springs break unexpectedly; Mercedes is cooperative on replacement. Brake lines also rust and are flagged at MOT. Park sensor cables deteriorate prematurely.
The central display in the instrument cluster dims heavily in warmth or fails completely. The defect often cannot be permanently resolved by software updates.