My Peugeot 407 recently started showing engine management system faulty. Pls can this be fixed

Yes it can be fixed but what to recommend first is a problem. I appreciate the information you provided but it is not enough to provide you with an accurate solution. This current fault could be caused by a number of possibilities. 02 Sensor, Camshaft Position Sensor, Fuel Pressure, Cylinder Compression, CAT, MAF, Vacuum Leak, Misfire or Other Related Ignition Failure. If the car arrived at my shop I would perform a preliminary check. Look for an Engine Light. Pull Codes and look at some live data. Look under the hood for and problems. How does the wiring look? Any strange or bad smells? How does the engine sound? How about the engine oil? Is it over due? How is the level? Preventive maintenance will adversely affect the life and performance of all vehicles. Depending on how you want to proceed. I would as you to look around and gather as much diagnostic information as you can. I can not promise that I can help you but I may be able to. You are the eyes and ears. Please write back, tell me everything that you noticed and found and I will do my best.