Converting kPa to psi involves multiplying the kPa value by 0.145038. However, obtaining consistent oil pressure readings through OBDII using a “Service 9” request with a specific PID can be challenging. Compatibility varies significantly between car brands and even models within the same brand.
Accessing manufacturer-specific data, like oil pressure, through OBDII isn’t always straightforward. For instance, some manufacturers, like Porsche in the past, tightly controlled access to this data, even when it was readily available to their diagnostic computers. While diagnostic tools could access extensive data streams, including oil temperature and pressure, the specific PIDs and commands weren’t publicly available.
Even with access to the OBDII bus and the ability to monitor message traffic, obtaining the necessary PID for oil pressure requires deciphering the communication between the diagnostic tool and the vehicle’s engine controller. This involves analyzing the commands sent by the diagnostic tool and the corresponding responses from the controller. Identifying the correct request and response pattern for oil pressure can be time-consuming and requires specialized knowledge. Furthermore, some manufacturers now restrict the data that technicians can access and print, further complicating the process of obtaining specific PIDs. This limitation prioritizes factory access to detailed vehicle data.
