On an automotive scan tool or diagnostic equipment, "ISO" and "SAE" reversed typically refer to the two primary communication protocols used in modern vehicles for onboard diagnostics and data exchange between the vehicle's electronic control modules and the diagnostic tool. These protocols are known as ISO 15765-4 and SAE J1979.
When you see "ISO & SAE reversed" on a car scan tool or diagnostic device, it likely means that the tool has the ability to switch between these two communication protocols, allowing it to work with a broader range of vehicles from different regions and manufacturers.
The U0100 trouble code indicates a communication problem between your vehicle's Engine Control Module (ECM) and the Powertrain Control Module A (PCA A). This code is typically associated with a network communication issue within the vehicle's onboard diagnostic system. If possible, let me know what system is causing issues so I can go into the diagnostics.
BTW, welcome to PA. I'm near Pittsburgh. LOL
Saturday, September 23rd, 2023 AT 7:10 PM