Transmission Input and Output Speed Sensors

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The transmission speed sensors (turbine and output shaft) are analog inductive sensors that produce an AC sine wave similar to an ABS/ASC wheel speed sensor. The AC signal frequency is proportional to the rotation speed of the monitored components:

The turbine speed sensor scans a pulse wheel attached to the forward clutch housing.
The output shaft speed sensor scans a pulse wheel attached to the rear ring gear.

The GS 20 monitors these signals along with the engine speed signal (CAN) to calculate transmission slip ratio for plausibility and for the adaptive pressure control function. The sensors are monitored for plausible signals, opens and shorts. Specific fault codes are stored for defects with these sensors.