C70 Reduced Engine Power

Fault code + reduced power sounds familiar. Did the car ever have any aftermarket chip tuning? Often, those tunes aren't properly optimized and can mess with the car's computer (ECU). The ECU controls all sorts of engine functions, and a bad tune can cause it to throw codes and limit power to protect itself. Was the error code something related to fuel mixture, timing, or boost pressure? That could give you a clue.

Yes, the previous owner mentioned a performance enhancement chip installed by a third-party provider. Given the fault code and reduced power, this seems increasingly likely as the root cause. Could you elaborate on the potential risks associated with such modifications, and whether reverting to the original factory settings might resolve the issue?

Okay, that pretty much confirms my suspicion. Those cheap tunes often push the engine beyond its safe limits, which triggers the ECU to go into limp mode (reduced power). Reverting to the factory settings is definitely worth a try, but it might require a visit to a workshop that can reflash the ECU with the original Volvo software. They should also be able to properly diagnose if the chip tuning has caused any lasting damage. Basically, the car is protecting itself from the dodgy tuning.

Your insights were incredibly helpful. I consulted a trusted mechanic, who confirmed that the fault code was indeed a consequence of the faulty chip tuning. The car computer was successfully reset to the default manufacturer's settings for 180€. The engine power has been fully restored, and the error is gone. Thanks again for your assistance.