Engine Speed Signal

Engine Speed Signal (RPM)








The Engine Speed Signal is required by the TCM to calculate the shift points. The RPM signal is provided by [1][2]DME as a processed signal that indicates RPM.

TD: The "TD" input is a pulsed square wave signal. The frequency of the signal is directly proportional to RPM.

TR: Used only on the E32 750iL and M70 850i, the "TR" input is an AC pulse wave signal. The frequency is also directly proportional to RPM.


NOTE: Later model vehicles equipped with CAN bus do not require a dedicated engine speed signal since engine speed is provided via CAN bus.