Mercedes B Klasse Engine Stalling Resolved

That sensor fault sounds suspicious given the symptoms. Engine stalling and reduced power often point to fuel pressure issues. It could be the sensor itself, but check the wiring and connections. A loose or corroded connector can cause a faulty signal. Is it running rough all the time or does it come and go?

Thanks. I wiggled the connector a bit, seemed okay but I didn't check for corrosion closely. It seems worse when the engine is cold. Once it warms up it's slightly better, but still not great. Could a bad sensor cause that, and is there any way to test it?

The cold start issue makes the sensor even more likely. A faulty sensor can send incorrect readings to the engine control unit, causing problems, especially when the engine is trying to adjust its fuel mixture during warm-up. Testing those sensors usually requires specialized equipment. Given the symptoms and the code, replacing the sensor is a reasonable next step, but it might not be the only potential problem. A quick shop visit to confirm might be worth it before replacing parts.

Thanks for the advice. I took it to a local mechanic as suggested. It was indeed the rail pressure sensor. They replaced it, and the total cost was 240€. Runs like new again, no more engine stalling!