Grandland X Brake Booster Pressure Sensor Error

I had something similar with my Grandland X! I had poor braking effect and the error message too. I'm no expert, but what exactly did they do during the service? Did they mess with the hydraulic brakes?

During the service, the brake fluid was completely replaced. Could this process, if not executed correctly, lead to air entering the system and subsequently affecting the brake booster pressure sensor?

Yep, that sounds very familiar. Replacing the brake fluid could be the culprit. If they didn't bleed the system properly, air in the lines can definitely cause issues with the booster. To be honest, I'd take it to a workshop to have them check it out properly. Brake performance isn't something to mess with, vehicle safety first!

I followed your suggestion and took the car to a local workshop. It turned out that the brake system bleeding had indeed been performed incorrectly, leading to the brake booster pressure sensor failure. The replacement parts and labor cost me approximately 90€. I appreciate your assistance in diagnosing the issue.