Just a few days ago the car went into "safe mode" meaning lost the biggest part of its horsepower and at the same time the preheaters warning lamp was blinking. After a visit to a mechanic he told me that the obd indindicated several malfunctions such as, faulty preheater No 3, EGR valve problem and low turbo pressure. After thinking a lot and after seeing that the EGR valve was in good condition we just replaced the above mentioned preheater. The cost was not low (290 € just for the preheater) but as they mentioned it is a complicated part that includes a pressure sensor that can cause not only malfunctions but can mislead the mechanic to search the problem elsewhere.