Link ecu fuel pressure sensor 499000-6121 For TOYOTA 

Diesel  CR PRESSURE SENSORS Fuel pressure sensor, commonly referred to as the fuel pressure sensor, it is installed at one end of the oil rail to measure the fuel pressure in the common rail pipe.    It is a part of vehicle’s fuel system and designed to monitor the fuel pressure that is present at the fuel rail.  The sensor sends this signal to the ECU, which then uses it to make adjustments to the vehicle’s fuel and timing.   Link ecu fuel pressure sensor 499000-6121