17958/P1550/005456 1 17958/P1550/005456 - Boost Pressure Controle Valve (N75): Control Deviation 1.1 Possible Symptoms 1.2 Possible Causes 1.3 Possible Solutions 17958/P1550/005456 - Boost Pressure Controle Valve (N75): Control Deviation Possible Symptoms Irregular behaviour Reduced power output Limp mode Possible Causes Hoses/Pipes incorrect connected, disconnected, blocked or leaking Charger Pressure Control defective Solenoid Valve for Boost Pressure Control (N75) defective Turbocharger defective Possible Solutions Check Hoses/Pipes to/between Components Check Charge Pressure Control Check Solenoid Valve for Boost Pressure Control (N75) Check turbocharger Thanks for the info, been back to garage and replaced maf sensor (again), had all fault codes reset and car seems to be running ok now. Will keep an eye on it tho, just incase.. Many thanks, Graham