D12 - erratic oil pressure gauge

My oil pressure gauge is reading erraticly. Sometimes high psi and then zero. I have the fault code MID 128 PID 100 FMI 3, which indicates an electrical fault. I understand that there are two oil sensors on the D12. One is a temperature / pressure sensor and one is just a pressure sensor, which is the same type of sensior as the fuel pressure sensor. There is a big price difference between the two, $230 and $70. Does anyone know which sensor feeds the oil pressure gauge?. Engine operates as normal when fault is active, so I am thinking the ECM must read the pressure of a separate sensor from the dash gauge or it would shut the engine down if it read zero pressure. My oil temperature readout is working fine. Cluster gauge test indicates no faults.

thanks in advance.

 

New sensor in. No more issues. It was the $237 one.