The Powertrain Control Module (PCM) controls multiple sensors, controllers, and electronic components that the vehicle is equipped with. One of these is the Oil Pressure Sensor (OPS) in the engine. This information is sent to the PCM as a voltage reading. Depending on the vehicle model, the oil pressure value may be transmitted to a gauge in the instrument cluster. In this way, the driver knows the oil pressure. If the gauge is missing, there will be a warning light indicating a problem.
The setting of the OBD2 DTC P0523 occurs when the PCM observes a value above the set level in the OPS sensor. This sensor works with a 5-volt circuit. Therefore, if the voltage is higher than the above mentioned, the Check Engine lamp will illuminate next to this code.