Electronic Control Module (ECM)
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| Illustration 1 | g06114574 |
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Machine ECM (1) Controller (2) J1 Connector (3) J2 Connector | |
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| Illustration 2 | g06117000 |
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Connectors of Machine ECM (2) J1 Connector (3) J2 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 two connectors (J1 and J2). The inputs and outputs to the ECM can be viewed through the Caterpillar Electronic Technician (Cat ET). Input and output information can also be viewed using the Operator Monitor.
The ECM also communicates with sensors and other control modules via the Controller Area Network (CAN) data link. The data link is bi-directional, allowing the machine ECM to both receive and send information with the engine ECM. The machine ECM also communicates to input and output components that are directly connected to the switch panel. The switch panel is used to link input and output components to the machine ECM via the CAN data link.
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.
| Machine ECM Connector J1 Contact Descriptions(1) | ||
|---|---|---|
| No. | Function | Type |
| 1 | Ground | Ground |
| 2 | PRV 8-10 Return | PRV Return |
| 3 | PRV 4-7 Return | PRV Return |
| 4 | + Battery | Battery (+) |
| 5 | PRV 1-3 Return | PRV Return |
| 6 | Straight Travel Pressure Sensor | Analog Active Input |
| 7 | CAN 4 + : Control Data Link | CAN 3 + |
| 8 | CAN 2 + : Machine Data Link | CAN 2 + |
| 9 | CAN 1 + : J1939 | CAN 1 + |
| 10 | Location Code 1 | Switch To Ground 1 |
| 12 | Boom Up Control Pilot Pressure Sensor | Analog Active Input |
| 13 | Right Travel Pressure Sensor | Analog Active Input |
| 14 | Standard Implement Pilot Pressure Sensor/Left Travel Pressure Sensor | Analog Active Input |
| 15 | 5V Supply | 5V Supply 1 |
| 16 | Joystick Pilot Pressure Sensor/Implement Pressure Sensor | Analog Active Input |
| 17 | Boom Down Control Pressure Sensor | Analog Active Input |
| 18 | Stick In Control Pressure Sensor | Analog Active Input |
| 20 | 8V Supply | 8V Supply 1 |
| 22 | Hydraulic Lock Solenoid | PRV 1 |
| 23 | Swing Brake Solenoid | PRV 2 |
| 24 | Travel Speed Solenoid | PRV 3 |
| 25 | Bucket In Control Pressure Sensor | Analog Active Input |
| 26 | CAN 4 - : Control Data Link | CAN 3 - |
| 27 | 2 - : Machine Data Link | CAN 2 - |
| 28 | CAN 1 - : J1939 | CAN 1 - |
| 29 | One Touch Low Idle Switch | Switch To Ground 8 |
| 32 | Stick Out Control Pressure Sensor | Analog Active Input |
| 33 | Swing Control Pressure Sensor | Analog Active Input |
| 34 | Analog & PWM Return 1 | Analog & PWM Return 1 |
| 38 | Analog & PWM Return 2 | Analog & PWM Return 2 |
| 41 | Key Switch | Key Switch |
| 42 | Boom Regeneration PRV | PRV 4 |
| 43 | Straight Travel Solenoid | PRV 5 |
| 49 | Switch To Ground Return 1 | Switch To Ground Return 1 |
| 50 | Location Code Enable/Disable | Switch To Ground 4 |
| 54 | Pump 1 Pressure Sensor | PWM Input 1 |
| 55 | Pump 2 Pressure Sensor | PWM Input 2 |
| 56 | NFC 1 Pressure Sensor | PWM Input 3 |
| 57 | NFC 2 Pressure Sensor | PWM Input 4 |
| 58 | Hydraulic Lock Cancel Switch | Switch To Battery 1 |
| 59 | CTWT Removal Switch | Switch To Battery 2 |
| 61 | NFC 1 Solenoid | PRV 6 |
| 62 | NFC 2 Solenoid | PRV 7 |
| 68 | Switch To Ground Return 2 | Switch To Ground Return 2 |
| 69 | Left Joystick Switch 1 (Upper) | Switch To Ground 11 |
| 70 | Right Joystick Switch 1 (Upper) | Switch To Ground 12 |
| 71 | Left Joystick Switch 2 (Fore) | Switch To Ground 13 |
| 72 | Right Joystick Switch 2 (Fore)/Smart Boom Cancel | Switch To Ground 14 |
| 73 | Boom Cylinder Head Pressure Sensor | PWM Input 5 |
| 74 | Boom Cylinder Rod Pressure Sensor | PWM Input 6 |
| 75 | Thumbwheel - LH | PWM Input 7 |
| 76 | Thumbwheel - RH | PWM Input 8 |
| 77 | Bucket Cylinder Head Pressure Sensor | PWM Input 16 |
| 79 | Boom 2 Up Solenoid | PRV 8 |
| 80 | Boom Down Solenoid | PRV 9 |
| 81 | Power Shift Solenoid | PRV 10 |
| (1) | Contacts that are not listed are not used. |
| Machine ECM Connector J2 Contact Descriptions(1) | ||
|---|---|---|
| No. | Function | Type |
| 86 | Attachment Stem 4 Status | Switch To Ground 18 |
| 87 | Analog & PWM Return 4 | Analog & PWM Return |
| 88 | Boom Up Limit Solenoid For Crane | PRV 17 |
| 89 | Bucket Out Limit Solenoid | PRV 18 |
| 90 | CAN 3 + : J1939 for CGC | CAN 4 + |
| 91 | CAN 3 - : J1939 for CGC | CAN 4 - |
| 92 | 8V Supply | 8V Supply 2 |
| 93 | Sensor Supply Return/Switch To Ground Return 3 | Sensor Supply Return/Switch To Ground Return 3 |
| 96 | Attachment Stem 2 Retract Assist Solenoid | PRV15 |
| 97 | Attachment Stem 2 Extend Assist Solenoid | PRV 16 |
| 98 | Boom Angle Sensor | PWM Input 11 |
| 100 | Analog & PWM Return 3 | Analog & PWM Return 3 |
| 101 | 5V Supply | 5V Supply 2 |
| 104 | Attachment Stem 1 Retract Assist Solenoid | PRV 13 |
| 105 | Attachment Stem 1 Extend Assist Solenoid | PRV 14 |
| 106 | Auxiliary Pedal 2 Control Pressure Sensor | Analog Active Input 9 |
| 107 | Auxiliary Pedal 1 Control Pressure Sensor | Analog Active Input 10 |
| 108 | Boom Angle Sensor | Analog Active Input 11 |
| 109 | Stick Angle Sensor | Analog Active Input 12 |
| 110 | Bucket Position Sensor | PWM Input 9 |
| 111 | Stick Angle Sensor | PWM Input 10 |
| 112 | Variable Relief 1 Solenoid | PRV 11 |
| 113 | Variable Relief 2 Solenoid | PRV 12 |
| 117 | PRV 13-14 Return | PRV 13-14 Return |
| 118 | PRV 15-16 Return | PRV 15-16 Return |
| 119 | PRV 11-12 Return | PRV 11-12 Return |
| (1) | Contacts that are not listed are not used. |
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| Illustration 3 | g02655338 |
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Underside of Soft Switch Panel | |
| Switch Panel Connector J1 Contact Descriptions | ||
|---|---|---|
| No. | Function | Type |
| 2 | Fuel Level Sensor | Analog Input |
| 3 | Hydraulic Oil Temperature Sensor | Analog Input |
| 4 | Analog Return | Analog Return |
| 5 | A / C Unit | Switch to Ground |
| 7 | Refuel Start Switch | Switch to Ground |
| 8 | Capsule Filter Plugged Switch | Switch to Ground |
| 9 | Fine Swing Switch | Switch to Ground |
| 10 | Hydraulic ATT Filter Plugged Switch | Switch to Ground |
| 11 | OLWD Warning Alarm Enable Switch | Switch to Ground |
| 13 | Boom Low Press Relief Enable Switch | Switch to Ground |
| Switch Panel Connector J2 Contact Descriptions | ||
|---|---|---|
| No. | Function | Type |
| 1 | Machine CAN Data Link + | CAN + |
| 2 | Machine CAN Data Link - | CAN - |
| 4 | Washer | Switch to Ground |
| 5 | Wiper Int - 3 | Switch to Ground |
| 6 | Wiper Int - 6 | Switch to Ground |
| 7 | Wiper Low | Switch to Ground |
| 11 | Smart Boom Down Switch | Switch-to-Ground |
| 12 | Smart Boom Up/Down Switch | Switch-to-Ground |
| Switch Panel Connector J3 Contact Descriptions | ||
|---|---|---|
| No. | Function | Type |
| 1 | +B | +Battery |
| 2 | GND | Ground |
| 3 | Key Switch | Key Switch |
| 4 | Swing Priority Solenoid | On/Off |
| 5 | Quick Coupler Bypass Cut Solenoid | On/Off |
| 6 | Fine Swing Solenoid | On/Off |
| 7 | Heavy Lift Solenoid | On/Off |
| 8 | Caution Lamp for Crane | On/Off |
| 9 | Boom Down Electric Check Solenoid for STBM (EC1) | On/Off |
| 11 | Boom Up Electric Check Solenoid for STBM (EC2) | On/Off |
| 12 | Travel Alarm | On/Off |
| 13 | Quick Coupler Uncoupling Solenoid | On/Off |
| 14 | Boom Low Press Relief Enable Solenoid | On/Off |
| 15 | Cab Lamp Relay | Relay |
| 16 | Boom Lamp Relay | Relay |
| 17 | Fault Alarm | Relay |
| 19 | Alternator R Term | Freq In - R Term |
| 20 | Quick Coupler Unlock Switch | Switch-to-Ground |
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.
In some cases the operator is provided a manual switch that can be used to change a condition of the machine.
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| Illustration 4 | g06115468 |
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| Illustration 5 | g06115475 |
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Sensor output | |
The values in Table 6 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Operating Pressure | 5 MPa |
| Supply Voltage | +5 ± .25 V |
| Output Signal | Analog |
| Output Range | 0.5 to 4.5 V |
| Pin Assignment | 1: Voltage
2: Ground 3: Signal |
The low-pressure sensors include:
- Implement pressure sensor
- Left travel pressure sensor
- Right travel pressure sensor
- Swing Control Pressure Sensor
- Boom Down Control Pressure Sensor
- Boom Up Control Pressure Sensor (If equipped with Smartboom)
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| Illustration 6 | g02263393 |
Note: The values in Table 7 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Operating Pressure | 10 MPa |
| Supply Voltage | +7V ~ +14V |
| Output Signal | 500 ± 100 Hz (PWM) |
| Output Range | 5% ~ 95% |
The low-pressure sensors include:
- Negative Flow Control 1 Pressure Sensor
- Negative Flow Control 2 Pressure Sensor
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| Illustration 7 | g02263513 |
Note: The values in Table 8 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Operating Pressure | 50 MPa |
| Supply Voltage | +7V ~ +14V |
| Output Signal | 500 ± 100 Hz (PWM) |
| Output Range | 5% ~ 95% |
The high-pressure sensors include:
- Boom Cylinder Head End Pressure Sensor
- Boom Cylinder Rod End Pressure Sensor (If equipped with Smartboom)
- Pump 1 Pressure Sensor (drive pump)
- Pump 2 Pressure Sensor (idler pump)
Hydraulic Oil Temperature Sensor
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| Illustration 8 | g03344952 |
Note: The values in Table 9 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Constant Voltage | Temperature | Restance (Ohms) |
| 12V DC | |
3268 Ω |
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1000 Ω | |
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653 Ω | |
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360 Ω | |
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148 Ω | |
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68 Ω | |
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34 Ω |
The temperature sensor for the hydraulic oil informs the ECM of the temperature of the hydraulic oil. The sensor sends an analog signal to the Machine ECM indicating hydraulic oil temperature.
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| Illustration 9 | g03234397 |
Note: The values in Table 10 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Rating | +32V MAX |
| Contact Postion | Level A - CLOSED
Level B - OPEN |
The hydraulic oil level switch monitors the hydraulic oil in the tank. When the hydraulic oil level is above the normal operating level, the switch OPENS. When the hydraulic oil drops below the normal operating level, the switch CLOSES. This switch is in the normally open position, when the switch is not installed on the machine.
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| Illustration 10 | g03234836 |
The hydraulic filter switch is a differential pressure switch. The switch measures the pressure differential between the return port at the hydraulic tank and the hydraulic tank pressure. If the pressure differential is greater than the specification the switch OPENS. A "Hydraulic Return Filter Plugged" warning message will be displayed on the monitor.
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| Illustration 11 | g02655636 |
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Standard Right Joystick (1-Button) (1) One Touch Low Idle Switch (2) One Touch Low Idle Switch Connections | |
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| Illustration 12 | g02658859 |
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Optional Right Joystick (3-Button, Trigger Switch) and Schematic Symbol (1) One Touch Low Idle Switch (SW-3) (2) One Touch Low Idle Switch (SW-3) Connections | |
Note: SW-2 is a trigger switch and is not shown in Illustration 12.
The one touch low idle switch (1) is located on the top or on the front of the right joystick (see Illustrations 11 and 12). The one touch low idle switch will automatically reduce engine speed to 1150 RPM. Both the right and the left joysticks must be in the neutral position before the engine speed is reduced.
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| Illustration 13 | g03230240 |
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Left Joystick (2-button, Slide, Trigger Switch) (1) Horn Switch (SW-3) (2) Horn Switch (SW-3) Connections | |
When horn switch is depressed, power is sent to the horn relay. The horn relay sends power to the horn.
Note: Your machine may not be equipped with all of the controls that are described in this topic.
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| Illustration 14 | g06127403 |
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Right Side Control Panel (1) Engine speed control (2) Power mode (3) Travel speed control (4) Automatic engine speed control (AEC) (5) Travel alarm switch (6) Work tool control (7) Heavy lift control (Not Equipped) (8) Window washer (9) Window wiper (10) Light switch (11) Rear view camera (12) Quick coupler control (13) Empty (14) Radio mute (15) Lower window wiper (16) Lower window washer (17A) Boom pressure control switch (17B) Fine swing control (18) Overload warning device | |
(1)" Engine Speed Dial Control Switch" This switch is used for the selection of the engine speed. The position of the engine speed dial is indicated on the operator monitor. Engine speed dial (1) is a 10 - -position switch. The selected position is displayed on operator monitor.
(2)" Power Mode" This switch is used for the selection of the power mode. The power mode can be changed from high hydraulic power to standard power to economy mode. The monitor will indicate the mode that is selected.
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| Illustration 15 | g02160606 |
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High Power Mode | |
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| Illustration 16 | g02160607 |
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Standard Power Mode | |
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| Illustration 17 | g02160612 |
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Economy Power Mode | |
(3)" Travel Speed Control" This switch is used to select the travel speed of the machine. When the LOW SPEED position is selected, the "turtle" indicator will illuminate. When AUTO position is selected, the "rabbit" indicator will illuminate. When the engine start switch is on, the travel speed control switch is always set at the LOW SPEED position.
(4)" Automatic Engine Speed Control" This switch is used for selection of the Automatic Engine Speed Control (AEC). The AEC system operates in three modes. The AEC automatically reduces engine speed when the machine is inactive. The AEC system will be inoperable while the backup switch of the electronic controller system is in the MAN position.
(5)" Travel Alarm Cancel Switch" This switch is used to stop the travel alarm from sounding. Press the switch in order to stop the alarm. The indicator lamp will turn on. The travel alarm will sound when the travel lever or the travel pedal is activated.
(6)" Work Tool Control" This switch is used for tool selection on machines with the optional tool control system. When this switch is activated, a tool selection menu is displayed on the monitor and tool options can be selected. Press the switch repeatedly in order to change the selected work tool.
(8)" Window Washer" As long as this switch is depressed, the window washer fluid will spray from the nozzle. The window wiper will also operate while the switch is depressed.
(9)" Window Wiper" Press this switch one time to activate the long window wiper interval function. Press this switch a second time to activate a short interval window wiper function. Press this switch three times to activate a continuous window wiper function. Press this switch a fourth time the window wiper function is stopped.
(10)" Light Switch" Press this switch once to active the work light mounted on the chassis and the work lights mounted on the cab. Press this switch a second time to active the work light mounted on the chassis, the work lights mounted on the cab, and the work lights mounted on the boom. When the switch is pushed a third time, all of the work lights are off.
(11)" Rear View Camera" If equipped, this switch is used to toggle the images that are shown on the monitor in the cab. The camera is mounted on the rear of the counterweight.
(12)" Quick coupler control" Press the top of the switch to retract the wedge and engage the quick coupler onto the work tool. Move the switch for the quick coupler to the UNLOCKED position to extend the wedge. Use this position only during the coupling or uncoupling of the work tool. The hydraulic system is pressurized when the switch is in this position.
Note: An alarm will sound whenever the switch is in the UNLOCKED or LOCKED position.
For further details, see Operation and Maintenance Manual, "Quick Coupler Operation".
(14)" Radio mute" Press the switch to mute the radio. Press the switch again to un-mute the radio.
(15)" Lower window wiper" Push down on the top of the switch to turn on the lower window wiper. Push down the bottom portion of the switch to turn off the lower window wiper.
(16)" Lower window washer" Push down on the top of the switch and keep the switch depressed to activate the lower window washer. While the switch is depressed, the washer fluid will spray from the nozzle.
(17A)" Boom pressure control" If equipped, press the switch to turn on the boom control pressure function. The boom pressure control function improves controllability for low load operation such as raking up rocks by reducing vibration and shock.
(17B)" Fine swing control" If equipped, push down on the top of the switch to activate the fine swing control. When the fine swing control is ON, the swing parking brake is released. Swing control improves during deceleration of a swing because the swing is allowed to drift instead of stopping abruptly.
Push down on the bottom of the switch to turn off the fine swing control. Operate the machine with the fine swing control in the OFF position when the machine is on a slope. Operate the machine with the fine swing control in the OFF position when great swing forces are required. For example, digging on a sidewall requires great swing force. Operate the machine with the fine swing control in the OFF position to control the motion with the swing brake.
(18)" Overload warning device" Press the switch to activate the overload warning device.
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| Illustration 18 | g02140333 |
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Key Start Switch | |
The key start switch is an input of the engine and pump controller. The key start switch informs the ECM of an attempt to start the engine. Then, the ECM initiates the start procedure.
The starting switch is a four position switch, and connects the battery supply terminal B to the other terminals.
Usually the position of the switch is the OFF position. At this time the connected terminals are the B and C terminals only.
When the switch is in the ON position, the connected terminals are B and R only. The keyswitch will remain in this position without handling.
When the switch is in the Start position, the connected terminals are B, R, and S. The keyswitch must be handled to remain in this position.
When the keyswitch is in the EMERGENCY STOP position, the connected terminals are B and A only. The keyswitch must be handled to remain in this position.
During normal machine operation, the start terminal of the key start switch is open. If the key start switch is placed in the START position, the start terminal will close. +Battery voltage is supplied to the start terminal. When all starting conditions are satisfied, the ECM sends a +battery signal to the start relay and engine cranking begins.
Note: After the key start switch is initially turned to the START position, the switch will not return to the START position from the ON position. The switch must be turned to the OFF position first. Then, the switch can be turned to the START position.
The ECM responds to decisions by sending electrical signals to the outputs. The outputs can create an action or the outputs can provide information to the operator or the service technician.
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| Illustration 19 | g01158530 |
Note: The values in Table 11 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Rated Voltage | 24 VDC |
| Coil Resistance | 41.5 ± 2.1Ω (T=20° C) |
The On/Off solenoids include:
- Swing brake solenoid
- Travel speed solenoid
- Straight travel solenoid
- Hydraulic lock solenoid
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| Illustration 20 | g03678894 |
Note: The values in Table 12 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Rated Voltage | 24 VDC |
| Coil Resistance | 22.4 ± 1.0 Ω (T=20° C) |
The On/Off solenoid in Illustration 20 includes:
- Swing Priority Solenoid
- Boom Up Electric Check Solenoid Valve (If equipped with Smartboom)
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| Illustration 21 | g03679000 |
Note: The values in Table 13 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Rated Voltage | 24 VDC |
| Coil Resistance | 24.0Ω (T=20° C) |
The On/Off solenoid in Illustration 21 includes:
- Boom Down Electric Check Solenoid Valve (If equipped with Smartboom)
Proportional Reducing Solenoid Valve
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| Illustration 22 | g02703776 |
Note: The values in Table 14 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Current Range | 0 mA ~ 700 mA |
| Coil Resistance | 15.0 ± 0.75Ω (T=20° C) |
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| Illustration 23 | g06126858 |
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A - Port pressure (kPa) vs Current (mA) | |
The proportional reducing solenoid valve is used on machines equipped with tool control. The P-Port is blocked and does not allow pressure to the A-port. Therefore, the machine ECM must apply current to the PRV in order to sent pressure to the A-port of the PRV.
The PRV's include:
- Negative Flow Control 1 Limit PRV
- Negative Flow Control 2 Limit PRV
- Power Shift Pressure PRV
Reverse Proportional Reducing Solenoid Valve
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| Illustration 24 | g02304374 |
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Valve cutaway, hydraulic schematic symbol, and electrical connector designation | |
Note: The values in Table 15 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Current Range | 0 mA ~ 700 mA |
| Coil Resistance | 15.0 ± 0.75Ω (T=20° C) |
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| Illustration 25 | g02304414 |
Reverse PRV's have the P-port open to the A-port with no current applied. Therefore, the machine ECM applies current to the PRV in order to decrease the pressure at the A-port.
The reverse PRV's include:
- Boom Regeneration PRV
- Boom Down Solenoid (If equipped with Smartboom)
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 switch panel. The switch panel then sends the fuel level information over the data link to the monitor. The monitor uses this information to display the fuel level.
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| Illustration 26 | g06113868 |
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Schematic of the data link circuit | |
The action alarm SOUNDS in order to alert the operator when a high emergency condition is present. For example, the engine oil pressure decreases below a set value.
The travel alarm SOUNDS in order to alert the area that the machine is moving.