Transmission Speed Signals

Transmission Speed Signals









4HP 24 & A4S 310/270R: The transmission control module monitors the output shaft (road speed) signal along with the engine speed (TD or CAN) to calculate transmission slip ratio for plausibility and to maintain the adaptive pressure control function.

The road speed signal is also used to calculate the shift points.

A5S 310Z, A5S 440Z, A5S 560 Z & A5S 360R: These transmissions additionally monitor the input shaft (turbine speed) signal along with the engine and output speed signals.

With this additional signal, the transmission control module can monitor internal clutch slip with more accuracy as well as monitoring the slip of the torque converter lock up clutch.

With the addition of the input shaft (turbine shaft) speed sensor, the transmission control module is now able to monitor much more accurately the slip time during shifts and vary clutch application or release pressure accordingly for overlap shift control.

The input shaft speed signal also allows the TCM to monitor the slip of the torque converter lock up clutch.

Both the turbine speed sensor and output speed sensor are analog inductive type sensors that produce an AC Voltage.

The frequency of the induced voltage impulses (and AC voltage) increase with the increase of speed.