2007 Mazda6 P0471 Code: Is There an Exhaust Pressure Sensor on This Model?

Hi, I own a 2007 Mazda6 with a 2.3L engine and currently have 85,000 miles on it. About a month ago, the check engine light activated and the OBD2 diagnostic tool returned a P0471 code — indicating an issue with the Exhaust Pressure (EP) sensor range or performance. However, the vehicle's performance has not improved in any way. I visited a Mazda dealership, where they informed me that the 2.3L engine in my 2007 Mazda6 does not have a dedicated exhaust pressure sensor. I confirmed this through a thorough visual inspection of the engine bay and relevant components. Another technician suggested that the EP sensor might be integrated into the EGR valve — but this seems unlikely given my understanding of how an exhaust pressure sensor functions mechanically and electrically. I've conducted multiple electrical and mechanical checks on the EGR valve, all of which show normal readings and no visible damage or faults. My question is: Is the EGR valve in this model actually part of a combined EP sensor system? If so, what should I do next? I'm hesitant to replace the EGR valve due to cost concerns and the risk of coolant leaks — especially since there's no evidence that it's malfunctioning or causing performance issues. Can anyone confirm whether the P047 or EGR valve is a single unit on this engine? Any advice would be greatly appreciated.