Engine speed: Diagnostics

A malfunction will generate a diagnostic trouble code primarily in Trionic.

When bus communication with Trionic ceases, diagnostic trouble code P1921 will be generated and the transmission goes 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).