Lanos S Hatchback L4-1.6L DOHC D-TEC MFI (1999)
Transmission Speed Sensor: Description and Operation
AUTOMATIC TRANSMISSION INPUT (SHAFT) SPEED SENSOR (A/T ISS)
The Automatic Transmission Input Shaft Speed Sensor (A/T ISS) is a magnetic inductive pickup that relays information relative to transaxle input
speed to the Powertrain Control Module (PCM). The PCM uses transaxle input speed information to control line pressure, Torque Converter Clutch
(TCC) apply and release and transaxle shift patterns. This information is also used to calculate the appropriate operating gear ratios and TCC
slippage.
The Input Speed Sensor (ISS) mounts on the transaxle case under the channel plate and next to the drive sprocket. An air gap of 0.26 - 2.90 mm
(0.010 - 0.114 inch) is maintained between the sensor and the teeth on 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 ISS. Higher vehicle speeds induce a higher frequency
and voltage measurement at the sensor.
Sensor resistance should measure between 625 - 725 ohms at 20°C (68°F). Output voltage will vary with vehicle speed from a minimum of 0.5 volts
AC at 550 RPM to 200 volts at 7000 RPM.
