 | |
| Illustration 1 | g00279578 |
Electronic Control Module (ECM) (1) Connector J1. (2) Connector J2. | |
The transmission electronic control module (ECM) makes decisions in order to control the operation of the transmission. The decisions are based on signals that are received through various inputs. Information that is stored in the memory of the ECM is also used. The transmission ECM sends commands through the outputs. The inputs and outputs of the transmission ECM are connected to the machine harness through two 40-pin connectors (J1 and J2). The ECM is located inside the cab. The ECM is inside an enclosure behind the shifter. See Testing And Adjusting, "Electrical Components And Connector Locations". There are no visual indicators on the ECM. Information concerning the electronic transmission control is shown on the Caterpillar Monitoring System. The ECM sends the information to the Caterpillar Monitoring System on the CAT Data Link.
Note: The ECM is not serviceable. If the ECM is damaged or faulty the ECM must be replaced.
Inputs
The machine has several input devices. Input devices inform the transmission ECM of the operating conditions of the machine. The machine has switch inputs and sensor inputs. Switches provide a signal to the switch inputs of the transmission ECM that is open, grounded, or +battery. Sensors provide a constantly changing signal to the transmission ECM. The inputs to the transmission ECM are listed in the two tables below.
Outputs
The transmission ECM responds to decisions by sending electrical signals through the outputs. The outputs can create an action or the outputs can provide information to the transmission ECM. The outputs for the transmission ECM are listed in the two tables below.
Input/Output
The CAT®Data Link is used to communicate with other electronic control modules on the machine. The data link is bidirectional. The data link allows the ECM to receive information. The data link allows the ECM to send information. The data link allows the sharing of information with other electronic control modules. A sample of the information that is passed between electronic control modules through the data link is shown below.
| Contact Description of ECM 40-Pin Connector J1 (1) | ||
|---|---|---|
| No. (2) | Function | Type |
| 1 | (+) Battery | Power |
| 2 | Ground | Ground |
| 3 | CAT Data Link - | Input/Output |
| 4 | Solenoid #2 | Solenoid Output |
| 5 | Ground | Ground |
| 6 | (+) Battery | Power |
| 7 | Solenoid Return | Output Return |
| 8 | Start Relay | Solenoid Output |
| 9 | CAT Data Link + | Input/Output |
| 10 | Solenoid #1 | Solenoid Output |
| 11 | Solenoid #4 | Solenoid Output |
| 12 | Differential Lock Lamp | Solenoid Output |
| 14 | Differential Lock Switch | Switch Input (open/grnd) |
| 15 | Switch/Sensor Return | Ground |
| 16 | Switch/Sensor Return | Ground |
| 17 | Solenoid #3 | Solenoid Output |
| 20 | Third Gear Switch | Switch Input (open/grnd) |
| 23 | Sixth Gear Switch | Switch Input (open/grnd) |
| 24 | Second Gear Switch | Switch Input (open/grnd) |
| 26 | Redundant Neutral Switch | Switch Input (open/grnd) |
| 29 | Fourth Gear Switch | Switch Input (open/grnd) |
| 30 | First Gear Switch | Switch Input (open/grnd) |
| 31 | Reverse Direction Switch | Switch Input (open/grnd) |
| 35 | Fifth Gear Switch | Switch Input (open/grnd) |
| 36 | Park Brake Pressure Switch | Switch Input (open/grnd) |
| 37 | Neutral Switch | Switch Input (open/grnd) |
| 39 | Forward Direction Switch | Switch Input (open/grnd) |
| 40 | Key Start Switch | Switch Input (open/grnd) |
| ( 1 ) | The ECM responds to an active input only when all the necessary conditinons are satisfied. |
| ( 2 ) | The connector contacts that are not listed are not used. |
| Contact Description of ECM 40-Pin Connector J2 (1) | ||
|---|---|---|
| No. (2) | Function | Type |
| 1 | Solenoid #6 | Solenoid Output |
| 2 | Converter Drive Indicator Lamp | Output |
| 3 | Solenoid Return | Output Return |
| 5 | Brake Pedal Input | Sensor Input |
| 6 | Lockup Clutch Pressure Input | Sensor Input PWM |
| 7 | Solenoid #5 | Solenoid Output |
| 8 | Lock Up Clutch | Solenoid Output |
| 10 | Ripper Position Sensor | Sensor Input PWM |
| 11 | Neutralizer Pedal Input | Sensor Input PWM |
| 13 | Differential Lock Solenoid | Solenoid Output |
| 14 | Torque Converter Speed Sensor | Sensor Input Freq |
| 18 | Articulation Position Sensor | Sensor Input PWM |
| 19 | Brake Lamp Relay | Solenoid Output |
| 20 | Torque Converter Speed Sensor + | Sensor Input Freq |
| 23 | Transmission Speed Sensor - | Sensor Input Freq |
| 24 | Engine Speed Sensor + | Sensor Input Freq |
| 29 | Transmission Speed Sensor + | Sensor Input Freq |
| 35 | Engine Speed Sensor | Sensor Input Freq |
| 37 | Backup Alarm | Solenoid Output (ON/OFF) |
| ( 1 ) | The ECM responds to an active input only when all the necessary conditions are satisfied. |
| ( 2 ) | The connector contacts that are not listed are not used. |