C70 Diesel Engine Stalling and Power Loss

I had a similar issue with my C70, though mine is a petrol version. The symptoms sound familiar. The check engine light and reduced power are classic signs of fuel delivery problems. Did you notice any engine misfire or rough idling before the stalling became persistent? Have you checked the fuel injection system or any of the car sensors?

Yes, there was occasional engine misfire, particularly when accelerating from a standstill. I have not checked the fuel injection system or the car sensors, but all hints points to the fuel volume regulator. Did replacing the high-pressure pump resolve the issue in your case, or did it turn out to be something else?

In my case, replacing the high-pressure pump resolved the issue. Considering the misfires and stalling you're experiencing, and that you're suspecting the fuel volume regulator, a defective high pressure pump seems like the most plausible explanation. I would recommend taking it to a trusted workshop to get a diagnostic done to confirm that it's the fuel pump, and not something else.

Thanks, that confirms my suspicions. I appreciate the advice. I took it to the workshop, and they confirmed that the fuel volume regulator was defective and that the high pressure pump needed replacement. The repair cost came to 1510€. Hopefully, that will resolve the issue for good.