Circuit Description

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The automatic transmission input shaft speed (AT ISS) sensor is a three-wire magnetic pick-up sensor that is mounted externally to the transmission. The AT ISS sensor utilizes the main idler gear teeth, located on the mainshaft, to generate a voltage signal of varying frequency, that corresponds to the rotational speed of the mainshaft. The AT ISS signal is sent to the powertrain control module (PCM) and is used to calculate the vehicle speed. Simultaneously, the signal from the automatic transmission output shaft speed (AT OSS) sensor is used to calculate the vehicle speed. The PCM compares the vehicle speed calculated from both speed sensors and uses this comparison for diagnosis of the speed sensors.

If the PCM detects an unreasonably large change in the AT ISS speed, in a short period of time, DTC P0718 sets. DTC P0718 is a type B DTC.