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Home >> Chevrolet >> 2007 >> Optra LS, Standard >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Automatic Transaxle - ZF 4HP 16 - Specifications, Component Locations And Repairs >> Description and Operation >> Electronic Component Description >> Automatic Transaxle Output Speed Sensor (A/T OSS)
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Automatic Transaxle Output Speed Sensor (A/T OSS)

The vehicle A/T output speed sensor (OSS) is a magnetic inductive pickup that relays information about vehicle speed to the transmission control module (TCM). The TCM uses this information to control the following functions:

Fig 1: View Of Speed Sensor Rotor
GM1256059Courtesy of GENERAL MOTORS CORP.

The OSS mounts in the case at the speed sensor rotor, which is pressed onto the spur gear. An air gap of 0.1-1.3 mm (0.004-0.050 in) is maintained between the sensor and the teeth on the spur gear. The sensor consists of a permanent magnet surrounded by a coil of wire. As the differential rotates, the OSS generates an AC signal.