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| Illustration 1 | g03307257 |
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| Illustration 2 | g01309473 |
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ECM Connectors and Contacts | |
The Implement ECM determines actions that are based on input information and memory information. After the Implement ECM receives the input information, the ECM sends a corresponding response to the outputs. The inputs and outputs of the Implement ECM are connected to the machine harness by two 70 contact connectors (J1 and J2). The ECM sends the information to the Caterpillar Electronic Technician (Cat ET) on the Cat Data Link.
Note: The ECM is not serviceable. The ECM must be replaced if the ECM is damaged. Replace the ECM if a failure is diagnosed.
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| Illustration 3 | g03420198 |
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The cushion hitch ECM and connectors | |
The cushion hitch ECM determines actions that are based on input information and memory information. After the cushion hitch 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 12 contact connectors (J1 and J2). The ECM sends the information to the Caterpillar Electronic Technician (Cat ET) on the Cat Data Link.
To aid in diagnostics of certain types of electrical circuits that are controlled by the ECM, an internal "pull up voltage" is connected to ECM switch and sensor signal input contacts. An above normal voltage is internally connected to the ECM signal input circuit through a resister.
During normal operation, the switch or sensor signal will hold the circuit low or at a certain signal amplitude, however, circuit conditions such as a loss of power to the component, a disconnection, or an open circuit will allow the circuit to be pulled high by the ECM pull-up voltage. This condition will result in an above normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 03 (voltage above normal) diagnostic code for the affected circuit.
The types of ECM input circuits that have pull-up voltage present are:
- Pulse Width Modulated (PWM) sensor input circuits
- Switch to Ground Input switch input circuits
- Active analog (voltage) input signal circuits
- Passive analog (resistance) input signal circuits
To aid in diagnostics of electrical circuits that are controlled by the ECM, an internal "pull down voltage" is connected to ECM switch to battery type input circuits.
During normal operation, the switch contacts that are allowing the connection to a voltage source will hold the circuit high. When circuit conditions such as a loss of power to the switch supply voltage, a disconnection in the switch circuit or an open circuit will allow the circuit to be pulled low by the ECM pull-down voltage. This condition will result in a below normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 04 (voltage below normal) diagnostic code for the affected circuit.
| Implement ECM Contact Description J1 Contact Descriptions(1) | ||
|---|---|---|
| No.(2) | Type | Function |
| 10 | Cat Data Link + | Cat Data Link + |
| 12 | Sourcing Driver Output | Pilot Solenoid |
| 13 | Battery Return | Battery - |
| 20 | Cat Data Link - | Cat Data Link - |
| 22 | Analog Input | Hydraulic Oil Temperature |
| 23 | Battery Return | Battery |
| 27 | Switch to Ground Input | ECM Location 1 |
| 31 | Battery Power Input | Battery + |
| 32 | Switch to Ground Input | ECM Location Enable |
| 35 | Switch to Ground Input | Load Assist Mode Switch (N/O) |
| 38 | Battery Power Input | Battery + |
| 40 | Switch to Ground Input | Load Assist Mode Switch (N/C) |
| 41 | Switch to Ground Input | Sequence Assist Mode Switch (N/O) |
| 42 | Switch to Ground Input | Sequence Assist Mode Switch (N/C) |
| 44 | Sensor Power Output | 8 V Sensor Supply |
| 45 | Sensor Power Return | 8 V Sensor Return |
| 46 | Battery Power Input | Battery + |
| 48 | Sourcing Driver Output | Bowl Raise Solenoid |
| 49 | Sourcing Driver Output | Bowl Lower Solenoid |
| 50 | Sourcing Driver Return | PWM Drivers 1 - 4 Return |
| 51 | Sourcing Driver Output | Ejector Forward Solenoid |
| 52 | Sourcing Driver Output | Ejector Return Solenoid |
| 54 | Sourcing Driver Return | PWM Driver 11-12 Return |
| 55 | Sourcing Driver Return | PWM Driver 9-12 Return |
| 56 | Sensor Power Return | Sensor Power Return |
| 57 | Battery Return | Battery - |
| 58 | Sourcing Driver Output | Apron Raise Solenoid |
| 59 | Sourcing Driver Output | Apron Lower Solenoid |
| 60 | Sourcing Driver Return | PWM Driver 5-8 Return |
| 63 | Switch to Ground Input | Cushion Hitch Switch (N/O) |
| 64 | Switch to Ground Input | Cushion Hitch Switch (N/C) |
| 65 | Sourcing Driver Output | Cushion Hitch Leveling Solenoid |
| 66 | Sourcing Driver Output | Cushion Hitch Enable Solenoid |
| 69 | Sensory Power Output | 10V Sensor Supply |
| 70 | Battery Return | Battery - |
| (1) | Contacts that are not listed are not used. |
| (2) | The connector contacts that are not listed are not used. |
| Implement ECM Contact Description J2(1) | ||
|---|---|---|
| No.(2) | Type | Function |
| 2 | Sourcing Driver Output | Bail Solenoid |
| 4 | Sourcing Driver Return | On/Off Driver Return |
| 8 | Sourcing Driver Return | Load Return 2 |
| 16 | PWM Input | Cushion Hitch Position Sensor |
| 17 | PWM Input | Apron Cylinder Position Sensor |
| 18 | PWM Input | Bowl Cylinder Position Sensor |
| 22 | Return | Sensor / Driver Return |
| 24 | PWM Input | Bowl Lever Position Sensor |
| 25 | PWM Input | Ejector Lever Position Sensor |
| 26 | PWM Input | Apron Lever Position Sensor |
| 30 | Switch to Ground Input | Implement Lockout Switch (N/O) |
| 31 | Switch to Ground Input | Implement Lockout Switch (N/C) |
| 33 | PWM Input | Apron Cylinder Rod End Pressure Sensor |
| 34 | PWM Input | Ejector Cylinder Head End Pressure Sensor |
| 35 | PWM Input | Ejector Cylinder Rod End Pressure Sensor |
| 40 | PWM Input | Bowl Cylinder Rod End Pressure Sensor |
| 41 | PWM Input | Bowl Cylinder Head End Pressure Sensor |
| 52 | Switch to Ground Input | Bail Switch (N/O) |
| 53 | Switch to Ground Input | Bail Switch (N/C) |
| 56 | CAN Data Link + | CAN A Data Link + |
| 59 | Switch to Ground Input | Cushion Hitch to Implement Pilot Pressure Filter Bypass Switch |
| 63 | Return | Sensor Driver Return |
| 64 | CAN Data Link + | CAN B Data Link + |
| 65 | CAN Data Link - | CAN B Data Link - |
| 67 | CAN Data Link + | CAN A Data Link + |
| 68 | CAN Data Link - | CAN A Data Link - |
| 70 | Can Data Link - | CAN A Data Link - |
| (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. |
| Cushion Hitch ECM 1 Contact Description J1 Contact Descriptions(1) | ||
|---|---|---|
| No.(2) | Type | Function |
| 5 | Battery Return | Ground |
| 6 | Battery Power Input | Battery + |
| 9 | CAN Data Link + | CAN A Data Link + |
| 10 | CAN Data Link - | CAN A Data Link - |
| (1) | Contacts that are not listed are not used. |
| (2) | The connector contacts that are not listed are not used. |
| Cushion Hitch ECM 1 Contact Description J2(1) | ||
|---|---|---|
| No.(2) | Type | Function |
| 1 | Sourcing Driver Return | Voice Coil - |
| 2 | Analog Return | Thermistor Return |
| 3 | Sourcing Driver Return | Position Sensor Return |
| 4 | PWM Input | Position Sensor |
| 6 | Analog Input | Pressure Sensor |
| 7 | Sensor Voltage Supply | Pressure Sensor Supply |
| 8 | Sensor Voltage Supply | Hall Effect Supply |
| 9 | Analog Input | Voice Coil Hall Effect |
| 10 | Analog Return | Hall Effect Return |
| 11 | Analog Sensor | Thermistor |
| 12 | Sourcing Driver Output | Voice Coil + |
| (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. |
| Cushion Hitch ECM 2 Contact Description J1 Contact Descriptions(1) | ||
|---|---|---|
| No.(2) | Type | Function |
| 5 | Battery Return | Ground |
| 6 | Battery Power Input | Battery + |
| 9 | CAN Data Link + | CAN A Data Link + |
| 10 | CAN Data Link - | CAN A Data Link - |
| (1) | Contacts that are not listed are not used. |
| (2) | The connector contacts that are not listed are not used. |
| Cushion Hitch ECM 2 Contact Description J2(1) | ||
|---|---|---|
| No.(2) | Type | Function |
| 1 | Sourcing Driver Return | Voice Coil - |
| 2 | Analog Return | Thermistor Return |
| 8 | Sensor Voltage Supply | Hall Effect Supply |
| 9 | Analog Input | Voice Coil Hall Effect |
| 10 | Analog Return | Hall Effect Return |
| 11 | Analog Sensor | Thermistor |
| 12 | Sourcing Driver Output | Voice Coil + |
| (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. |
The machine has several different types of input devices. The ECM receives machine status information from the input devices and determines the correct output action that is needed in order to control machine operations based on memory and software parameters. The machine utilizes the following types of inputs: switch type and sensor type.
Switches provide signals to the switch inputs of the ECM. The possible outputs of a switch are listed: an open signal, a grounded signal and + battery signal.
Sensors provide an electrical signal to the ECM that constantly changes. The sensor input to the ECM can be one of several different types of electrical signals such as: pulse width modulated (PWM) signals, voltage signals and frequency input signals. Each possible input to the ECM is listed in the tables for the 70-pin connectors.
Inputs provide information to the ECM in the form of sensors or switches.
Sensors provide information to the ECM about the intent of the operator or changing conditions. The sensor signal changes proportionally to the changing of operator input or changing conditions. The following types of sensor signals are used by the ECM.
Frequency - The sensor produces a signal and the frequency (Hz) varies as the condition changes.
Pulse width modulated - The sensor produces a signal. The duty cycle of the signal varies as the condition changes. The frequency of this signal is constant.
Analog - The ECM measures the voltage that is associated to a specific condition of the control.
Hydraulic Oil Temperature Sensor
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| Illustration 4 | g03325780 |
The hydraulic oil temperature sensor is a passive analog sensor. The sensor creates a different resistance depending on the temperature of the hydraulic oil. The variations in resistance cause a proportional variation in voltage. This voltage is measured at the ECM contact, and allows the ECM to determine the temperature of the hydraulic oil.
Cushion Hitch Cylinder Position Sensor
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| Illustration 5 | g03424049 |
The cushion hitch cylinder position sensor is a pulse width modulated position sensor. As the cushion hitch cylinder lengthens, the duty cycle of the pulse width modulated signal increases. Based on this duty cycle, the ECM is able to determine the location of cushion hitch cylinder.
Apron Thumb roller Position Sensor
The apron thumb roller position sensor is a pulse width modulated sensor located in the joystick handle. In the center position the duty cycle from the sensor is approximately 50%. As the thumb roller is moved the duty cycle of the sensor changes proportionally. Based on the duty cycle received the ECM is able to determine the operator request for apron movement.
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| Illustration 6 | g03325148 |
The cushion hitch pressure sensor is used to measure the pressure on the head end of the cushion hitch cylinder. The sensor is a pulse width modulated sensor. The duty cycle of the sensor is proportional to the measured pressure.
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| Illustration 7 | g03424942 |
The voice coil contains two sensors. A thermistor sensor, and a hall effect position sensor. The thermistor is a passive analog sensor and the output voltage is proportional to the temperature of the cushion hitch hydraulic oil. The ECM determines the temperature of the oil from the voltage received form the sensor. The position sensor is an active analog sensor that determines the location of an internal spoiler. The output voltage of the sensor is proportional to the position of spoiler. The ECM determines the location of the spoiler by the voltage received from the sensor.
Switches provide an open signal, a ground signal, or a +battery signal to the inputs of the ECM. Switches are open or closed.
- When a switch is open, no signal is provided to the corresponding input of the ECM. This “no signal” condition is also called “floating”.
- When a switch is closed, a ground signal or a +battery signal is provided to the corresponding input of the ECM.
Load Assist / Grade Control Mode Switch
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| Illustration 8 | g03422668 |
The load assist / grade control mode switch is a single pole momentary switch. The switch has a normally open contact and a normally closed contact. When the switch is activated, the normally open contact closes and the normally closed contact opens. The ECM normally open contact is pulled to a low voltage state and the normally closed contact floats to a high voltage state. The change in voltage state causes the ECM to toggle the operation of load assist or grade control.
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| Illustration 9 | g03422668 |
The sequence assist mode switch is a single pole momentary switch. The switch has a normally open contact and a normally closed contact. When the switch is activated, the normally open contact closes and the normally closed contact opens. The ECM normally open contact is pulled to a low voltage state and the normally closed contact floats to a high voltage state. The change in voltage state causes the ECM to toggle the operation of sequence assist.
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| Illustration 10 | g06228179 |
| (A) Cushion Hitch | |
The cushion hitch switch is a single pole switch. The switch has a normally open contact and a normally closed contact. When the switch is activated, the normally open contact closes and the normally closed contact opens. The ECM normally open contact is pulled to a low voltage state and the normally closed contact floats to a high voltage state. The change in voltage state causes the ECM to toggle the operation of the cushion hitch.
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| Illustration 11 | g03346014 |
The implement shutoff switch is a two pole switch. The switch has a normally connected and a normally open contact. When the switch is not depressed the normally connected contact is connected to the return, and the normally open contact floats to a high voltage state. When the switch is depressed, the normally open contact is connected to the return and the normally connected contact floats to a high voltage state. Based on the voltage state of the two ECM contacts, the ECM determines if the switch is depressed. The second pole on the switch allows the path of power from an ECM driver to flow through the switch to the shutoff solenoid.
Cushion Hitch Filter Bypass Switch
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| Illustration 12 | g03424806 |
The cushion hitch filter bypass switch is a single pole pressure switch. When the switch is closed under normal operation, the ECM contact is connected to a return contact. When the hydraulic pressure exceeds a set point, the switch opens. When the switch opens, the ECM contact floats to a high voltage from the ECM pull-up voltage. When the switch opens, the ECM alerts the operator that the cushion hitch filter is being bypassed.
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 13 | g03422260 |
The pilot solenoid is an on/off type solenoid that acts to lock out the implement system. The solenoid is part of the implement valve group and prevents pilot hydraulic oil from flowing to the rest of the valve bank. When the solenoid is energized, the pilot oil is allowed to flow and the implement system is enabled.
Note: The solenoid coils are not designed to operate using 24 DCV directly. The ECM sends a PWM signal of 24 V at a duty cycle that will provide the necessary current to the solenoid coils. Do NOT activate the coils by using 24 DCV (+battery). The life of the coils will be reduced drastically. A source of 12 DCV should be used, if the coils must be activated by not using the ECM.
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| Illustration 14 | g03425512 |
The cushion hitch enable solenoid is an on/off type solenoid. The ECM energizes the solenoid based on operator request. When the solenoid is energized, the cushion hitch system is activated.
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| Illustration 15 | g03347475 |
All proportional solenoids in the implement system are identical in construction, however function differently. Illustration 15 shows an example of a proportional solenoid in the implement system.
Note: The solenoid coils are not designed to operate using 24 DCV directly. The ECM sends a PWM signal of 24 V at a duty cycle that will provide the necessary current to the solenoid coils. Do NOT activate the coils by using 24 DCV (+battery). The life of the coils will be reduced drastically. A source of 12 DCV should be used, if the coils must be activated by not using the ECM.
Cushion Hitch Leveling Solenoid
The cushion hitch leveling solenoid controls the movement of the leveling valve spool. The solenoid is proportional, and depending on the duty cycle the solenoid shifts the leveling valve spool to send hydraulic oil to the head or rod end of the cushion hitch.
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| Illustration 16 | g03424942 |
The voice coil contains a driver that causes an internal spoiler to change positions. As current is applied to the coil, the force on the internal spoiler increases. The cushion hitch ECM uses temperature and position information to determine how much current to apply to the coil.
Electronic communication between the Chassis ECM, the Implement ECM, and the other control modules on the machine is conducted over data link circuits. The data link circuits allow the sharing of information with other electronic control modules. The data link circuits are bidirectional. The data link circuit allows the ECM to send information and to receive information.
The electronic communication system consists of two types of data link systems.
- Cat Data Link
- SAE J1939 (CAN) Data Link
The two types of data links are the main structure for communication between all of the control modules on the machine.
The SAE J1939 Data Link circuit is mostly used for faster operational communication between the control modules on the machine. The Cat Data Link is used for some of the internal communication that does not require the faster speeds and is used for communication with external devices such as the Caterpillar Electronic Technician (Cat ET) service tool.
The Cat Data Link is an input/output of the ECM. The data link uses the connector for the service port in order to communicate with the Caterpillar Electronic Technician. A data link connection is provided for the product link.
Note: The control for the product link provides a global positioning system for the machine.
The data link is bidirectional. The bidirectional link allows the ECM to input information and output information. The data link consists of the following parts: internal ECM circuits, the related harness wiring, the service tool connector and the connector for the product link. The Cat Data Link connects to the ECM at contact J1-10 (wire 893-GN(Green)) and contact J1-20 (wire 892-BR(Brown)).
- The ECM receives commands from the Cat ET in order to change the operating modes. The Cat ET will read the service codes that are stored in the memory of the ECM. The Cat ET will clear the service codes that are stored in the memory of the ECM.
- The ECM sends the input and the output information to the Caterpillar ET.
Note: An electronic control module that uses the Cat Data Link will have a module identifier. The MID for the Machine Electronic Control Module is 039.
A data link is required for communication with the service tool (Cat ET) and the electronic control modules as well as instrument clusters and other devices that use this communications protocol. The data link is not used in order to broadcast any diagnostic information.