RIM-ROLLER 9S8317 - Caterpillar

Illustration 1 g02875897
(1) Engine output speed sensor (Final installation on engine by OEM)
(2) Torque converter output speed sensor (Internal to transmission)
(3) Transmission output speed sensors Each speed sensor has two connections to the ECM (+ and −). For all of the speed sensors, "2" connector contact is the signal line and connector "1" contact is the return line. The speed sensors send an AC frequency signal (HZ) that matches the number of gear teeth passing the sensor per second to the ECM. The ECM compares the frequency from the speed sensor (HZ) to the number of pulses per revolution in order to determine the speed of the rotating components. The ECM uses the input from the speed sensors in order to regulate transmission shifts.The speed sensors are used to cross check and diagnose each other during normal operation. Cross check uses two transmission output speeds and the torque converter output speed. These speeds will validate and determine which transmission output speed sensor to use for shifting. Cross check compares the three speeds. If at least two speeds agree, the transmission shifts as expected. Otherwise shifting is inhibited and the lockup clutch is disengaged. The ECM periodically checks the value from the speed sensor. If an incorrect, erratic, or absent value is found, the ECM will log a service code (speed sensor diagnostic) that indicates a fault for a speed sensor circuit.There is one engine output speed sensor (1), one torque converter output speed sensor (2), and two transmission output speed sensors (3). All speed sensors are used to determine if any individual speed sensor has failed.