VALVE 5J9078 - Caterpillar

Sensors
Sensors provide information to inputs of the ECU about actual transmission conditions. The ECU receives information from the sensor for speed and temperature. The sensor signal will change in order to reflect changes in the monitored condition. The ECU sends this information out on the data link to the instrument clusters and other data link devices. The ECU recognizes three types of sensor signals.Frequency - The sensor produces an AC signal. The AC signal frequency (Hz) varies as the condition changes.Pulse width modulated - The sensor produces a digital signal. The duty cycle of the digital signal varies as the condition changes and the frequency of the digital signal is constant.Voltage - The sensor produces a voltage in reference to the measured condition. A change in the condition results in a change in voltage at the ECU signal input pin.Torque Converter Temperature Sensor
Illustration 1 g01213764
The torque converter temperature sensor that is located on the torque converter is a two wire passive thermistor type sensor. This type of sensor is used to measure the temperatures of the coolant, oil, and the inlet air. As the temperature of the torque converter oil changes, the resistance in the sensor will change. This change in resistance changes the voltage that is seen by the ECU for the sensor.Transmission Oil Temperature Sensor
Illustration 2 g01213764
The transmission oil temperature sensor that is located on the transmission sump is a passive thermistor type sensor that has two wires. As the temperature of the transmission oil changes, the resistance in the sensor will change. This change in resistance changes the voltage that is seen by the transmission ECU for the sensor.Oil Level Sensor (Transmission)
Illustration 3 g01824773
The oil level sensor measures the oil level using the Hall Effect. As fluid enters the bottom of the sensor the internal float moves axially toward the Hall Effect device. The result is an output signal between 1 V (empty) and 4 V (full) proportional to the fluid level. The sensor connects to the ECU at contact J1-21, contact J1-11, and contact J1-36.Engine Speed Sensor
Illustration 4 g01213770
Engine Speed SensorThe engine speed sensor for the transmission is a magnetic sensor.The engine speed sensor is an input to the ECU. The sensor is designed to inform the ECU about the speed of the engine. The ECU uses the information from the speed sensor in order to calibrate the transmission solenoids. The ECU uses the information from the speed sensor in order to enable the lockup clutch. Also, the information is used in order to disable the lockup clutch. The lockup clutch is turned off if the engine speed is too low. The lockup clutch is turned on if the engine speed is too high. This is done in order to prevent overspeeds of the engine or stalling of the engine.The engine speed sensor is a frequency sensor. The speed sensor is located on the flywheel housing. The sensor generates an AC signal from the ring gear teeth as the teeth pass the sensor. The ECU measures the frequency