In 2018, FCA upped their OBD2 security so that aftermarket scanners and other OBD2 devices are blocked from communicating. This cable bypasses that security, so that your Amp Steps, Edge CTS monitor, or scanner will work with no issues
2018+ Cummins Bypass Cable (also known as the Security Gateway Module Bypass Cable) can be used in multiple ways and on multiple platforms of Fiat Chrysler vehicles. This cable is meant to be installed and left in the vehicle. It is NOT intended to be uninstalled and re-used on other vehicles. Once installed, the OBD-II will still function normally.