The ability to monitor transmission temperature is very useful and is one of the biggest requests that we get. Transmission temperature is not available over generic OBD2 because it is not part of the OBD2 standard specification. Since transmission temperature is not part of the OBD2 standard, the method for accessing it is different for every vehicle manufacturer and vehicle. Some vehicles do not support reading transmission temperature at all over the OBD2 port.
Accessing transmission temperature requires enhanced diagnostics. Enhanced diagnostics essentially means accessing modules (ECUs) and PIDs that are manufacturer and vehicle specific and are not part of a universal standard. There are two options that you can explore to get access to transmission temperature, and both are described below.
The enhanced diagnostic add-ons that are available as an optional purchase include transmission temperature for most vehicles. We license the diagnostic data from the vehicle manufacturers, and the diagnostics are tailored to each specific vehicle. Since the diagnostic data comes directly from the vehicle manufacturer, the enhanced diagnostic add-ons provide the highest quality option for reading non-standard PIDs such as transmission temperature. If you want more information about determining whether enhanced diagnostics are available for your vehicle or purchasing an enhanced diagnostic add-on, see the Enhanced Diagnostics help article.
The name of the transmission temperature PID in the enhanced diagnostic add-ons varies for each vehicle manufacturer. Here are some common names that you can look for when configuring PIDs with an enhanced diagnostic add-on:
When trying to locate the transmission temperature PID, search for all or part of these names in the PID selector to locate the PID that applies to your vehicle. If you still cannot find the PID, then it's possible it is not supported by your vehicle.
Some vehicles might support more than one transmission temperature PID. For example, on some Toyota and Lexus vehicles, you might see PIDs with names A/T Oil Temperature 1 and A/T Oil Temperature 2. These are usually readings from different sensors in the vehicle, such as the oil pan sensor and torque converter sensor.
User-defined PIDs allow you to create your own PIDs by entering the PID definition. The PID definition includes items such as the PID mode, PID address, module address, and conversion equation. We are unable to provide custom PID definitions; however, some users have been able to find PID definitions by searching online. There are some PID definitions built into the app that you can import on the Settings > User-Defined PIDs page. We don't have a list of which vehicles support each of the built-in PID defintions.
See the User-Defined PIDs help article for more information about creating user-defined PIDs.