Shift Lever Position Sensor - The ECM must know the desired gear position. The switch for the shift lever provides a ground signal. The ground signal varies with the gear that has been selected.
Transmission Gear Position Sensor - The ECM must know the transmission gear that is engaged.
Transmission Output Speed Sensor (TOS) - The ECM must know the output speed of the transmission. The TOS sensor monitors the speed of the transmission output shaft and reports the information to the ECM.
Upshift Solenoid and Downshift Solenoid - The ECM must electrically shift the transmission. The ECM uses two separate outputs to the solenoids to shift the transmission. The transmission is always shifted one gear at a time. The ECM activates the solenoids electrically to shift the transmission.
(S/N: FDB) machines only
Transmission Output Speed Sensor (TOS) 1 & 2 - Both sensors provide input to the ECM. The sensors indicate the speed of the transmission output shaft to the ECM. The ECM will compare the signals from the sensors to determine if a sensor is malfunctioning. The ECM uses the sensor information to shift the transmission efficiently.
The items that follow are exceptions.
- The ECM will not shift the transmission from a forward or reverse gear into NEUTRAL, until the ground speed is under
8 km/h (5 mph) . Limiting the shift of the transmission discourages coasting in neutral at high speed, which reduces transmission life. For more information, see the topic in System Operation, "Neutral Coast Function". - The reverse gear will not become engaged until the ground speed is less than
4.8 km/h (3 mph) . The limiting helps protect the transmission from damaging directional shifts. - The ECM does not downshift when the operator selects a speed that is not appropriate for the current TOS. Automatic upshifting and/or downshifting will continue. The gear of the transmission and the gear selected for the transmission are identical until the TOS decreases to the downshift point of the selected transmission gear. The selected transmission gear now becomes the new top gear.
- The ECM shifts the transmission up one gear above the selected gear if the TOS reaches a critical value. This limiting helps protect the engine from overspeed. If the transmission is already in top gear, the lockup clutch is deactivated.
The ECM also controls other functions: hoist, "autolube" system, backup alarm, and start relay.
Note: All events regarding engine overspeed are recorded and available for examination. The examination of these events requires the use of the proper service tool. See the topic in System Operation, "Tattletale Function".
Three events are logged in the ECM.
- Transmission abuse
- Coasting in neutral
- Machine overspeed