Mercedes B Klasse Hybrid Fuel Consumption and Starting Issues

I have a B Klasse too, though not a hybrid. I had similar problems a while back. Higher fuel consumption and rough starts usually point to something messing with the air-fuel mixture. The throttle valve, or throttle body, controls how much air goes into the engine. Think of it like a tap. When you press the accelerator pedal, it opens the valve, letting in more air, which the engine then mixes with fuel to create power. 'Throttle position' is important because the car's computer uses that information to adjust the fuel injection. If the throttle position sensor is faulty, it can send incorrect signals, leading to poor engine performance. Have you checked the 'engine idle' speed? Is it unusually high or low?

Thanks for the explanation That makes sense I haven't checked the engine idle speed Where would I even find that information And how would a faulty 'accelerator pedal module' factor into all this

You can usually see the engine idle speed on your car's instrument cluster when the car is stationary and the engine is running. It's usually measured in RPM (revolutions per minute). It should be a steady number, somewhere around 700-900 RPM usually. The accelerator pedal module contains the sensor that tells the car how far down you've pressed the pedal. It's basically an electronic connection to the 'car throttle'. If it's defective, it might be sending the wrong signals to the engine, causing the throttle valve to open or close at the wrong times. Honestly, given the symptoms, it might be worth getting it checked by a workshop. Playing around with the throttle body can be tricky.

Thanks a lot for the advice I took it to a workshop, and you were right, the throttle valve was defective. They replaced the accelerator pedal module, and it cost around 205€. The car runs perfectly now