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Vehicle Speed Sensor

M/T  - Vehicle speed information is provided to the Powertrain Control Module (PCM) by the Vehicle Speed Sensor (VSS). The VSS is a permanent magnet generator that is mounted on the transaxle and produces a pulsing voltage whenever vehicle speed is over 3 MPH. The AC voltage amplitude and frequency increases with vehicle speed. The PCM converts the pulsing voltage into MPH. The PCM supplies the necessary signal to the instrument panel for speedometer, odometer operation and to the cruise control and multi-function alarm module.

A/T Input Shaft Speed Sensor  - The Automatic Transmission Input Shaft Speed Sensor (AT ISS) is a magnetic inductive pickup that relays information about the transmission input speed to the PCM. The PCM uses this information to control the line pressure, TCC apply and release, and the transmission shift patterns. This information is also used to calculate the appropriate operating gear ratios and TCC slippage. The AT ISS mounts on the transmission case under the channel plate next to the drive sprocket. An air gap of 0.010-0.114" (0.26-2.90 mm) is maintained between the sensor and the teeth of the drive sprocket. The sensor consists of a permanent magnet surrounded by a coil of wire. As the drive sprocket is driven by the turbine shaft, an AC signal is induced in the AT ISS. Higher engine speeds induce a higher frequency and voltage measurement at the sensor. Sensor resistance should be 625-725 ohms when measured at 68°F (20°C). Output voltage will vary with speed from a minimum of 0.5 volts AC at 550 RPM, to 200 volts AC at 7000 RPM.

A/T Output Shaft Speed Sensor  - The Automatic Transmission Output Shaft Speed Sensor (AT OSS) provides vehicle speed information to the PCM. The AT OSS is a permanent magnet generator mounted to the transmission case. The AT OSS produces an AC voltage as the transmission speed sensor rotor teeth pass through the sensor's magnetic field. The AC voltage level increases as the speed of the vehicle increases. The PCM converts the AC voltage into a digital signal. The PCM uses the vehicle speed signal to determine shift timing, Torque Converter Clutch (TCC) apply, TCC release, and gear ratio calculations.

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