Tesla Model 3 OBDII Adapter - models shipped prior to January 9, 1919
The Tesla Model 3 is an electric car with no emissions and so is exempt from federal air quality regulations requiring an Onboard Diagnostics Connector Version II providing engine data for emissions testing. So it doesn't have one.
But many third party devices such as Head's Up Display (HUD), fleet monitoring, and insurance monitoring use an OBDII connection to derive operational data from an OBDII port.
This adapter connects between two console connectors to monitor Model 3 Vehicle CAN bus for such data and then presents it on a standard OBDII female connector compliant with the J1979 protocol to provide Parameter Identifier (PID) values on request. In this way, you can use almost any OBDII device in the Tesla Model 3.
Additionally, the 240MHz ESP32 processor has built in WiFi wireless connectivity and software to emulate the ELM327 WiFi dongle available for OBDII. But the dongle isn't necessary as this device handles the WiFi communications directly - enabling smart phone apps such as Torque for Android or OBD2 Fusion for iOS. These apps present a graphical "dashboard" of information about the Tesla Model 3 operation in real time and actually allow you to use your smart phone as a head's up display.
This device installs conveniently on the rear lower side of your Tesla Model 3 console using no tools and monitors the Tesla Model 3 Vehicle CAN bus.
EVTV Model 3 CAN Adapter User Manual
TorquePro Tesla Model 3 DASH and PID file