| Contacts of Transmission Control Connector | ||
| No. | Function | Type |
| 1 | +Battery | Power |
| 2 | Ground | Ground |
| 3 | Auto/Manual Switch | Operational Input |
| 4 | Neutralizer Switch (High Pressure) (1) | Operational Input |
| 5 | Transmission Speed | Sensor Input |
| 6 | Engine Speed | Sensor Input |
| 7 | Speedometer Signal | Output |
| 8 | CAT Data Link + | Input/Output |
| 9 | CAT Data Link - | Input/Output |
| 10 | Unused | |
| 11 | Unused | |
| 12 | Downshift Switch | Operational Input |
| 13 | Parking Brake Limit Switch | Operational Input |
| 14 | Neutralizer Switch (Low Pressure) | Operational Input |
| 15 | Forward Input | Operational Input |
| 16 | Neutral Input | Operational Input |
| 17 | Reverse Input | Operational Input |
| 18 | Ride Control ON Switch | Operational Input |
| 19 | Load Check or Ride Control (2) (3) | Operational Input |
| 20 | Speed Input 1 | Operational Input |
| 21 | Speed Input 2 | Operational Input |
| 22 | Speed Input 3 | Operational Input |
| 23 | Speed Input 4 | Operational Input |
| 24 | Harness Code 1 | Harness Code Input |
| 25 | Harness Code 2 | Harness Code Input |
| 26 | Harness Code 3 | Harness Code Input |
| 27 | Harness Code 4 | Harness Code Input |
| 28 | Option Code 1 | Option Code Input |
| 29 | Option Code 2 | Option Code Input |
| 30 | Diagnostic Indicator | Output |
| 31 | Forward High Solenoid | Solenoid Output |
| 32 | Reverse Solenoid | Solenoid Output |
| 33 | Forward Low Solenoid | Solenoid Output |
| 34 | Transmission Speed Solenoid 1 | Solenoid Output |
| 35 | Transmission Speed Solenoid 2 | Solenoid Output |
| 36 | Transmission Speed Solenoid 3 | Solenoid Output |
| 37 | Ride Control or Load Check Relay (2) (3) | Solenoid Output |
| 38 | Parking Brake Alarm Relay | Solenoid Output |
| 39 | Solenoid Return | Solenoid Ground |
| 40 | Unused | |
| ( 1 ) | Rated Engine Speed for models 938G and IT38G |
| ( 2 ) | The load check relay is for the 928G, IT28G, and 924G. |
| ( 3 ) | Only one of the options can be installed. |
Electronic circuits within the ECM make shifting decisions. Electronic circuits control the transmission solenoid valves. The inputs of the ECM and the outputs of the ECM are connected to the wiring of the machine harness through a contact connector with 40 pins.
Input/Output
The CAT data link is used to communicate with the electronic service tool. The CAT data link is bidirectional. The ECM can receive information and the ECM can send information. This permits sharing of information with the electronic service tool.
Inputs
Several types of inputs provide information to the ECM.
Operational
The operational inputs provide information about operator requests to the ECM. These inputs receive information from the following components: the shift lever, downshift, neutralizer (high pressure and low pressure), ride control, parking brake and auto/manual switches. These switches provide the following inputs to the ECM: open, ground and battery signal.
Harness Code
The harness code inputs (connector contacts 24 through 27) tell the ECM the proper installed machine model. The harness code inputs are open or grounded by the machine harness. See the procedure Testing And Adjusting, "MID081 - CID 650 - FMI 02" to obtain specific information for the model.
Sensor
At each sensor input, an AC signal is present. The signal represents the transmission speed (connector contact 5) and engine speed (connector contact 6). The ECM measures the frequency (Hz) of the AC signals in order to determine the transmission speed and the engine speed. The ECM uses this speed information to make shifting decisions.
Option Code
The option code inputs (connector contacts 28 and 29) tell the ECM the attachments that are installed. Attachments can be the following items: ride control and load check.
Outputs
Diagnostic Indicator
When a system fault is detected, the ECM activates the warning indicator output (connector contact 30) and the diagnostic indicator is turned ON. The system fault indicator shows the fault by flashing ON and OFF.
Speedometer
The output of the speedometer (connector contact 7) sends the information from the transmission speed sensor to the speedometer. When there is a signal to the ECM from the transmission speed sensor the output from the speedometer is activated.
Solenoid
When a direction and gear are selected by the operator or the control, the ECM sends a voltage to the appropriate solenoid outputs which energize transmission solenoids. The solenoid outputs are connector contacts 31 through 36.