how to clear service def system see dealer

[MacMadison]

To clear a “Service DEF System” warning, first make sure the DEF tank has enough high-quality fluid. If the level is correct, drive the vehicle briefly to let the system reset. If the alert remains, a diagnostic scan is needed to read and clear DEF-related error codes, and some problems may require a dealer-level tool to run functions like reductant heater activation or a forced regeneration.