The Machine ECM will make decisions that are based on input data information and programming parameters that have been flashed to the ECM memory. After the ECM receives the input information, the ECM determines the correct response and sends an output signal to the appropriate device. The internal input circuits and the internal output circuits of the ECM are connected to the machine wiring harness by two contact connectors (J1 and J2).
Note: The ECM is not serviceable. If the ECM is damaged, the ECM must be replaced. The ECM failure is unlikely. If the ECM failure is suspected, contact the Technical Communicator at a local dealership for possible consultation with AVSpare before replacing the ECM. Replace the ECM only after all the other possible causes of a particular problem have been investigated.
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 resistor.
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. The pull-up voltage 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 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. The pull-down voltage 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.
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 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 Machine ECM is listed in the tables for the connectors.
The ECM sends electrical signals through the outputs. The outputs can create an action or the outputs can provide information to the ECM. The ECM can send output signals to the system components in one of several different electrical signal types such as: driver outputs, sinking driver outputs, sensor power supply outputs, and data link outputs. The possible outputs for the Machine ECM are listed in the tables for the connectors.
Communication between the Machine 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 ECM supports two types of data link systems.
- Cat® Data Link
- SAE J1939 Data Link
The two types of data links are the main structure for communication between all the control modules on the machine. More than one CAN data link system can be present on a machine. Dedicated CAN data link circuits can be used for communication between specific controls on the machine.
Communication between the Machine ECM and the other control modules on the machine are conducted over the J1939 Data Link circuit that is connected to each control module. The ECMs use the Cat Data Link to send and receive information from the Cat® Electronic Technician (ET) Service Tool.
A module identifier (MID) is assigned to each ECM on a machine. The MID for Machine ECM 1 is 299.
Note: The following tables list every possible connection for the Machine ECM. Depending on the attachments that are installed on your machine, some of the listed circuits may not be present.
| Machine ECM #1 Connector J1 Contact Descriptions (1) | ||
|---|---|---|
| No. | Function | Type |
| 1 | - Battery | Battery (-) |
| 2 | PRV 8-10 Return | PRV Return |
| 3 | PRV 4-7 Return | PRV Return |
| 4 | + Battery | Battery (+) |
| 5 | PRV 1-3 Return | PRV Return |
| 8 | CAN2 + | CAN2 + |
| 9 | CAN1 + | CAN1 + |
| 10 | Switch To Ground 1 | Switch To Ground 1 |
| 20 | 8V Supply 1 | 8V Supply 1 |
| 22 | PRV 1 | PRV 1 |
| 23 | PRV 2 | PRV 2 |
| 24 | PRV 3 | PRV 3 |
| 27 | CAN 2- | CAN2 - |
| 28 | CAN1 - | CAN1 - |
| 29 | Switch To Ground 8 | Switch To Ground 8 |
| 34 | Analog & PWM Return 1 | Analog & PWM return 1 |
| 35 | Analog Passive In 1 | Analog Passive In 1 |
| 37 | Fuel Level Sensor | Fuel Level Sender |
| 38 | Analog & PWM Return 2 | Analog & PWM return 2 |
| 41 | Key Switch 1 | Key Switch |
| 42 | PRV 4 | PRV 4 |
| 43 | PRV 5 | PRV 5 |
| 49 | STG Return 1 | STG Return 1 |
| 50 | Switch To Ground 4 | Switch To Ground 4 |
| 53 | Switch To Ground 7 | Switch To Ground 7 |
| 54 | PWM/Freq In 1 | PWM/Freq In 1 |
| 55 | PWM/Freq In 2 | PWM/Freq In 2 |
| 56 | PWM/Freq In 3 | PWM/Freq In 3 |
| 58 | PRV1 Power Supply | Switch To Battery 1 |
| 59 | Hyd Lock Sol Status (NC) | Switch To Battery 2 |
| 60 | Hyd Lock Status | Switch To Battery 3 |
| 61 | PRV 6 | PRV 6 |
| 62 | PRV 7 | PRV 7 |
| 67 | Switch To Ground 10 | Switch To Ground 10 |
| 68 | STG Return 2 | STG Return 2 |
| 71 | Foot SW for Hammer Ready | Switch To Ground 13 |
| 73 | PWM/Freq In 5 | PWM/Freq In 5 |
| 79 | PRV 8 | PRV 8 |
| 80 | PRV 9 | PRV 9 |
| 81 | PRV 10 | PRV 10 |
| (1) | Contacts that are not listed are not used. |
| Machine ECM #1 Connector J2 Contact Descriptions (1) | ||
|---|---|---|
| No. | Function | Type |
| 82 | Switch To Ground 15 | Switch To Ground 15 |
| 83 | Switch To Ground 16 | Switch To Ground 16 |
| 84 | Switch To Battery 4 | Switch To Battery 4 |
| 85 | Switch To Ground 17 | Switch To Ground 17 |
| 87 | Analog & PWM Return 4 | Analog & PWM Return 4 |
| 88 | PRV 17 | PRV 17 |
| 89 | PRV 18 | PRV 18 |
| 93 | SNSR Sply Return / STG Return 3 | STG Return 3 |
| 96 | PRV 15 | PRV 15 |
| 97 | PRV 16 | PRV 16 |
| 98 | PWM/Freq In 11 | PWM/Freq In 11 |
| 99 | PWM/Freq In 12 | PWM/Freq In 12 |
| 101 | 5V Supply 2 | 5V Supply 2 |
| 102 | PWM/Freq In 13 | PWM/Freq In 13 |
| 103 | PWM/Freq In 14 | PWM/Freq In 14 |
| 104 | PRV 13 | PRV 13 |
| 105 | PRV 14 | PRV 14 |
| 110 | PWM/Freq In 9 | PWM/Freq In 9 |
| 111 | PWM/Freq In 10 | PWM/Freq In 10 |
| 112 | PRV 11 | PRV 11 |
| 113 | PRV 12 | PRV 12 |
| 114 | PRV 17-18 Return | PRV 17-18 Return |
| 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 |
| 120 | + Battery | Battery (+) |
| 121 | + Battery | Battery (+) |
| (1) | Contacts that are not listed are not used. |
| BCM Connector Contact Descriptions (1) | ||
|---|---|---|
| No. | Function | Type |
| 1 | -B | Power Supply |
| 2 | On / Off Driver / Relay Return 9-12 | PRV 8-10 Return |
| 3 | Stem 1 Extens Eprv / Hyd Lock Return | PRV 4-7 Return |
| 4 | +B | + Battery |
| 5 | On / Off Driver / Relay Return 1-4 | PRV 1-3 Return |
| 8 | CAN 1+ | CAN2 + |
| 9 | CAN 2+ | CAN1 + |
| 16 | Engine Start Button LED (Green) | Analog Active In 4 |
| 17 | Engine Start Button LED (Red) | Analog Active In 5 |
| 18 | ECM (D6:CX) | Analog Active In 6 |
| 21 | Wake Up Input 1 (D6:CX) | Hall Effect In 1 |
| 23 | Main power relay | PRV 2 |
| 24 | M-ECM (Primary) Key Switch | PRV 3 |
| 27 | CAN 1- | CAN2 - |
| 28 | CAN2- | CAN1 - |
| 30 | Window Limit Switch (STG) | Switch To Ground 9 |
| 31 | Window Limit Switch (Return) | CAN 1 SHLD |
| 37 | Engine Key Switch (Sink) | Fuel Level Sender |
| 38 | Boom Light Relay | Analog & PWM Return 2 |
| 39 | Chassis / Cab Light Relay | Low Sink |
| 41 | Key Switch | Key Switch |
| 42 | Straight Travel Solenoid | PRV 4 |
| 44 | Wiper 1st Speed Relay | Ether 2 TX+ |
| 45 | Wiper 2nd Speed Relay | Ether 2 TX- |
| 61 | Stem 1 Extens EPRV | PRV 6 |
| 62 | Swing Brake | PRV 7 |
| 63 | Washer Relay | Ether 1 TX+ |
| 64 | Mute | Ether 1 TX- |
| 67 | Att Hydraulic Oil Filter Switch | Switch To Ground 10 |
| 68 | STG Return 5-6 | Switch To Ground Return 2 |
| 77 | Key Switch Normally Close (PTS) | PWM/Freq In 16 |
| 78 | Travel Speed Solenoid | VR+ |
| 80 | Engine Start Signal to Engine ECM | PRV 9 |
| (1) | Contacts that are not listed are not used. |