Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Sunfire and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

The automatic transmission input speed sensor (ISS) provides transmission input speed to the PCM. The ISS is a permanent magnet generator. The sensor mounts into the transmission case and maintains a slight air gap between the sensor and the drive sprocket. The ISS produces an AC voltage as the drive sprocket rotor teeth pass through the magnetic field of the sensor. The AC voltage level increases as the turbine shaft speed increases. The PCM converts the AC voltage into a digital signal. The PCM determines actual turbine speed using the digital signal. The PCM uses the input speed to calculate torque converter slip speed, and gear ratios.

When the PCM detects a low input speed and the vehicle has a large vehicle speed, then DTC P0717 sets. DTC P0717 is a type B DTC.

Fig 1: Automatic Transmission Input Speed Sensor (ISS) Schematic

Courtesy of GENERAL MOTORS CORP.