Electronic Control Module (ECM)
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| Illustration 1 | g06279698 |
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Machine ECM (1) Controller (2) J1 Connector (3) J2 Connector | |
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| Illustration 2 | g06279720 |
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86-Pin Connectors for Machine ECM (2) Connector (3) Connector | |
The output from the Machine ECM is based on input information from the sensors. The output commands are based on the software programmed into the control module. After the Machine ECM receives the input information, the ECM sends a corresponding response to the outputs. The inputs and outputs of the ECM are connected to the machine harness by one 70-pin connector. The inputs and outputs to the ECM can be viewed through the Cat® Electronic Technician (Cat ET) Service Tool. Input and output information can also be viewed using the Operator Monitor.
The ECM also communicates with sensors and other control modules using the CAN Data Link. The data link is bidirectional, allowing the Machine ECM to both receive and send information with the engine.
Note: Only the complete ECM is serviced (no lower levels components). The ECM must be replaced if the ECM is damaged. Replace the ECM if a failure is diagnosed.
The Cat Data Link is used to provide a connection for the service tool for troubleshooting, testing, and calibrations. The data link is bidirectional. The data link allows the ECM to receive information. The data link also allows the ECM to send information.
| Machine ECM Connector J1 Contact Descriptions(1) | ||
|---|---|---|
| No. | Type | Pin Description |
| 1 | Ground | LS Return J1-19 |
| 2 | Output | Swing Left Solenoid |
| 4 | Output | Swing Right Solenoid |
| 7 | Output | Swing Brake Unlock Solenoid |
| 10 | Output | Boom Extend Solenoid |
| 11 | Output | Stick Retract Solenoid |
| 12 | Output | Stick Extend Solenoid |
| 13 | Ground | Return of PWM J1-11, J1-12, J1-46, and J1-65 |
| 15 | Power | Power Return (8V) |
| 17 | Output | Bucket Retract Solenoid |
| 19 | Output | Hydraulic Lockout Solenoid |
| 36 | Ground | Return of PWM J1-02, J1-04, J1-10, and J1-57 |
| 46 | Output | Bucket Extend Solenoid |
| 56 | Power | Power Supply (8V) |
| 57 | Output | Boom Retract Solenoid |
| (1) | Contacts that are not listed are not used. |
| Machine ECM Connector J2 Contact Descriptions(1) | ||
|---|---|---|
| No. | Type | Pin Description |
| 2 | Output | Auxiliary 1 Port A Solenoid |
| 3 | Output | Right Travel Forward Solenoid |
| 4 | Output | Right Travel Reverse Solenoid |
| 5 | Output | Left Travel Forward Solenoid |
| 6 | Output | Left Travel Reverse Solenoid |
| 8 | Output | AUX 1 Port B Solenoid |
| 11 | Ground | Return of PWM J2-02, J2-13, J2-25, and J2-33 |
| 13 | Output | Blade Raise Solenoid |
| 14 | Ground | Return of PWM, J2-2, J2-8, J2-16, and J2-24 |
| 16 | Output | Implement Function 1 Port A Solenoid |
| 19 | Ground | Return of PWM J2-34, J2-41, J2-42, and J2-49 |
| 24 | Output | Implement Function 1 Port B Solenoid |
| 25 | Output | Blade Lower Solenoid |
| 26 | Ground | Return of PWM J2-03, J2-04, J2-05, and J2-06 |
| 33 | Output | Bypass Solenoid |
| 34 | Output | Implement Function 3 Port B Solenoid |
| 41 | Output | Implement Function 3 Port A Solenoid |
| 42 | Output | Implement Function 2 Port A Solenoid |
| 44 | Input | Main Hydraulic Pump Pressure Sensor |
| 46 | Input | Boom Cylinder Head End Pressure Sensor |
| 49 | Output | Implement Function 2 Port B Solenoid |
| 50 | Input | Boom Cylinder Rod End Pressure Sensor |
| 64 | Input | Dedicated Auxiliary Pump Pressure Sensor |
| (1) | Contacts that are not listed are not used. |
The inputs describe the status of the machine systems. Two types of inputs exist. The inputs can be either a switch type or a sensor type. Switches provide an open, a ground, or a + battery signal to the inputs of the controller. Sensors (frequency, PWM, or voltage) provide a changing signal to the sensor inputs of the controller. The controller will recognize the following types of sensor signals:
Analog - The sensor will produce a voltage signal that changes as the conditions that the sensor is sensing, changes.
Frequency - The sensor will produce an AC signal (sine wave or square wave) that varies in frequency (Hz) as the condition changes.
Pulse Width Modulated - The sensor produces a digital signal and varies the duty cycle as the condition changes. The frequency of the signal will remain constant.
Sometimes the operator is provided a manual switch that can be used to change a condition of the machine.
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| Illustration 3 | g02263513 |
The values in Table 3 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Operating Pressure | |
| Supply Voltage | +7V ~ +14V |
| Output Signal | 500 ± 100 Hz (PWM) |
| Output Range | 5% ~ 95% |
The high-pressure sensors include:
- Boom cylinder rod end pressure sensor
- Boom cylinder head end pressure sensor
- Main hydraulic pump pressure sensor
- Auxiliary pump pressure sensor
The ECM responds to inputs by sending electrical signals to the outputs. The outputs can create an action or the outputs can provide information to the operator or service technician. The outputs of the ECMs are listed in tables 1 and 2.
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| Illustration 4 | g06191494 |
Note: The values in Table 4 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Rated Voltage | 12 VDC |
| Coil Resistance | 8.1 ± 0.4Ω (T=20° C) |
The hydraulic lock solenoid is an output of the Machine ECM. The hydraulic lock solenoid is energized to enable the primary hydraulic pressure. The hydraulic lock solenoid is de-energized to disable the primary hydraulic pressure.
This solenoid is activated while the key switch is in the ON position and the hydraulic lock lever is in the UNLOCK position.
Proportional Reducing Solenoids
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| Illustration 5 | g06191521 |
Note: The values in Table 5 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Current | 1.5 A (max at 80° C ambient) |
| Rated Voltage | 12 VDC |
| Coil Resistance | 4.7 ± 0.2Ω (T = 20° C) |
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| Illustration 6 | g06237029 |
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A - Port pressure (kPa) vs Current (mA) | |
The P-Port is blocked and does not allow pressure to the A-port. Therefore, the machine ECM must apply current to the solenoid to send pressure to the A-port of the valve.
The boom extend and retract solenoids are an output of the Machine ECM. The boom extend and retract solenoids are activated when the joystick is moved to signal those functions.
Stick Extend/Retract Solenoids
The stick extend and retract solenoids are an output of the Machine ECM. The stick extend and retract solenoids are activated when the joystick is moved to signal those functions.
Bucket Extend/Retract Solenoids
The bucket extend and retract solenoids are an output of the Machine ECM. The bucket extend and retract solenoids are activated when the joystick is moved to signal those functions.
Auxiliary Supply/Return Solenoids
The auxiliary port A and B solenoids are an output of the Machine ECM. With an auxiliary tool connected and the auxiliary system activated, the auxiliary port A and B solenoids are activated when the joystick is moved to signal those functions.
Implement Function 1 Port A/Port B Solenoids
The implement function 1 port A and B solenoids are an output of the Machine ECM. With an auxiliary tool connected and the auxiliary system activated, the implement function 1 port A and B solenoids are activated when the joystick is moved to signal those functions.
Implement Function 2 Port A/Port B Solenoids
The implement function 2 port A and B solenoids are an output of the Machine ECM. With an auxiliary tool connected and the auxiliary system activated, the implement function 2 port A and B solenoids are activated when the joystick is moved to signal those functions.
Implement Function 3 Port A/Port B Solenoids
The implement function 3 port A and B solenoids are an output of the Machine ECM. With an auxiliary tool connected and the auxiliary system activated, the implement function 3 port A and B solenoids are activated when the joystick is moved to signal those functions.
The swing left and right solenoids are an output of the Machine ECM. The swing left and right solenoids are activated when the joystick is moved to signal those functions.
Right Travel Forward/Reverse Solenoids
The right travel forward and reverse solenoids are an output of the Machine ECM. The right travel forward and reverse solenoids are activated when the travel levers/pedals are moved to signal those functions or when the joystick travel is enabled and in use.
Left Travel Forward/Reverse Solenoids
The left travel forward and reverse solenoids are an output of the Machine ECM. The left travel forward and reverse solenoids are activated when the travel levers/pedals are moved to signal those functions or when the joystick travel is enabled and in use.
Blade Extend/Retract Solenoids
The blade extend and retract solenoids are an output of the Machine ECM. The blade extend and retract solenoids are activated when the joystick is moved to signal those functions.
The data link is a controller network used to pass information back and forth. The data link is designed to carry communications between the various controllers and the monitor. The data link is not a visible component. The network consists of internal control circuits and a wiring harness. The data link is bidirectional. The controllers can receive information and send information. Two 120 Ohm terminating resistors must be installed in the wiring harness in order for each data link to function properly.
An example of how the data link works would be the fuel level information. The fuel level sensor is connected to the machine ECM. The ECM then sends the fuel level information over the data link to the monitor. The monitor uses this information to display the fuel level.