Kickdown function: Diagnostics
In the event of a malfunction, a diagnostic trouble code will be generated primarily in the Trionic system.
When bus communication with the Trionic system ceases, diagnostic trouble code P1921 will be generated and the transmission will go into Limp-Home mode.
Inaccurate information on the bus causes diagnostic trouble code P1971 to be generated. Depending on the fault, the TCM may activate the emergency operation program (Limp-Home mode).