Sensors and Switches

The PCM controls the transmission electronic functions through input signals received from the engine and transmission sensors. The PCM uses these inputs to control line pressure, shift time, TCC and shift solenoids.

Item	Description
TFT sensor	This sensor is located in the main control. It is a temperature-sensitive device called a thermistor. The resistance value of the TFT sensor varies with temperature change. The PCM monitors the voltage across the TFT sensor to determine the temperature of the transmission fluid. The PCM uses this initial signal to determine whether a cold start shift schedule is necessary. The cold start shift schedule allows delayed shifts when the transmission fluid is cold to help warm the transmission fluid. The PCM also inhibits TCC operation at low transmission fluid temperatures and adjusts line pressure for temperature.
TR sensor	The park by wire dual range TR sensor indicates the state of the park system. The cable shift dual range TR sensor determines the customer selected shifter position.
TSS/ISSA (Turbine Shaft Speed/Intermediate Shaft Speed Assembly) sensor	The TSS/ISSA (Turbine Shaft Speed/Intermediate Shaft Speed Assembly) sensor is a Hall-effect type sensor that provides a turbine shaft or intermediate shaft speed signal to the PCM. The TSS (Turbine Shaft Speed) signal changes in frequency as the rotating speed of the trigger wheel, part of the B clutch cylinder, varies. The ISSA (Intermediate Shaft Speed Assembly) reads off of the reaction sun gear and is part of the TSS (Turbine Shaft Speed) sensor. The TSS/ISSA (Turbine Shaft Speed/Intermediate Shaft Speed Assembly) information is compared to engine rpm to determine TSS/ISSA (Turbine Shaft Speed/Intermediate Shaft Speed Assembly) performance. TSS/ISSA (Turbine Shaft Speed/Intermediate Shaft Speed Assembly) is also compared to the OSS to determine shift quality and clutch performance.
OSS sensor	The OSS sensor is a Hall-effect type sensor that provides an OSS signal to the PCM. The OSS signal changes in frequency as the rotating speed of the trigger wheel, part of the park gear, varies. The OSS is used for shift scheduling. The OSS is also compared to the TSS/ISSA (Turbine Shaft Speed/Intermediate Shaft Speed Assembly) to determine shift quality and clutch performance.
Transmission Fluid Pressure (TFP) sensor	Transmission Fluid Pressure (TFP) sensors for clutch A (TFP A) and B (TFP B) have been added to improve diagnostic capability for non-electrical (stuck solenoid or valve) faults. Pressure readings are used to monitor the status of specified clutch systems during operation.