Econoline E550 V10-6.8L VIN S (2003)
Transmission Speed Sensor: Description and Operation
4R100
Turbine Shaft Speed (TSS) Sensor
The turbine shaft speed (TSS) sensor is a magnetic pickup that sends the powertrain control module (PCM) information on the rotation speed of the coast
clutch cylinder assembly. The turbine shaft speed (TSS) sensor is mounted externally on the top of the transmission case. The PCM uses turbine shaft
speed TSS sensor signals to help determine electronic pressure control (EPC) pressure, shift scheduling the torque converter clutch (TCC) operation.
For diesel applications the PCM sends the TCC solenoid pulse-width modulated signals to smoothly engage the torque converter clutch.
Output Shaft Speed (OSS) Sensor - Gasoline Engines
The output shaft speed (OSS) sensor is a magnetic pickup that provides transmission output shaft rotation speed information to the powertrain control
module.
The OSS sensor is mounted externally on the top of the transmission extension housing. The powertrain control module (PCM) uses the OSS sensor
signal to help determine electronic pressure control (EPC) pressure, shift scheduling and torque converter clutch (TCC) operation.
Vehicle Speed Sensor (VSS) - 7.3L Diesel Only
The vehicle speed sensor (VSS)(model-dependent) is a variable reluctance sensor that sends an A/C frequency signal to the powertrain control module
(PCM). The VSS sensor signal is used by the PCM to calculate vehicle speed in mph and determine shift scheduling and electronic pressure control.
For diesel applications the VSS is used for output speed sensing, supplying the PCM with transmission output speed. The PCM then sends the TCC pulse
width modulated signals to smoothly engage the torque converter clutch.
