The 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. Refer to the correct pilot machine schematic to verify each input to the ECM.
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. Refer to the correct pilot machine schematic to verify each output to the ECM.
Communication between the 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 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 (Cat ET) Service Tool.
A module identifier (MID) is assigned to each ECM on a machine. For example, the MID for the Machine ECM is 299.
| Contact Description J1(1) | ||
|---|---|---|
| No.(2) | Function | Type |
| 1 | Key Switch Run | Key-On |
| 10 | AVS Datalink + | Cat Data Link (+) |
| 11 | +5V Sensor Supply | +5V Sensor Supply |
| 12 | PTO Winch Accumulator Sol / Hydraulic Low-Speed Lock | On/Off Sourcing Driver |
| 13 | -Battery (1) | Battery Return |
| 14 | A/C Switch Manual | Switch to Battery |
| 20 | AVS Datalink - | Cat Data Link (-) |
| 21 | +5V Sensor Return | +5V Sensor Supply / Return |
| 22 | Hydraulic Oil Temp Sender (Passive) | Passive Analog Input |
| 23 | -Battery (2) | Battery Return |
| 27 | Location Code 1 | Switch to Ground Input |
| 29 | Recirc Filter Temp (Cab Temp) | Passive Analog Input |
| 30 | Louver Temp Sensor | Passive Analog Input |
| 31 | +Battery (1) | Battery Power Input |
| 32 | Location Code Enable | Switch to Ground Input |
| 33 | Single/Dual Tilt Trigger SW N/C | Switch to Ground Input |
| 34 | Single/Dual Tilt Trigger SW N/O | Switch to Ground Input |
| 35 | Blade Manual Select SW (NC) | Switch to Ground Input |
| 37 | Fuel Level Sender | Active Analog Input |
| 38 | +Battery (2) | Battery Power Input |
| 39 | +Battery (3) | Battery Power Input |
| 40 | Blade Manual Select SW (N/O) | Switch to Ground Input |
| 41 | Blade Mode Select SW (N/C) | Switch to Ground Input |
| 42 | Blade Mode Select SW (N/O) | Switch to Ground Input |
| 43 | HYD Tank Pressure Sensor | Switch to Ground Input |
| 44 | 8V Power | 8V Power |
| 45 | 8V Return | 8V Return |
| 47 | +Battery (4) | Battery Power Input |
| 48 | Blade Raise | Sourcing Driver Output |
| 49 | Blade Lower | Sourcing Driver Output |
| 50 | Blade Solenoid Return | Sourcing Driver Return |
| 51 | Blade Tilt Left Solenoid | Sourcing Driver Output |
| 52 | Blade Tilt Right Solenoid | Sourcing Driver Output |
| 53 | Evaporator Freeze Probe Temp Sensor | Passive Analog Input |
| 54 | Quick Drop/Blade 2 Solenoid Return | PWM Driver Switched Return |
| 55 | PWM Driver Return | PWM Driver Switched Return |
| 56 | 10V Return | 10V Supply Return |
| 57 | - Battery (3) | Battery Return |
| 58 | Ripper Raise | Sourcing Driver Output |
| 59 | Ripper Lower | Sourcing Driver Output |
| 60 | PWM Driver Return | Sourcing Driver Return |
| 61 | Blade Angle Right | Sourcing Driver Output |
| 62 | Blade Angle Left | Sourcing Driver Output |
| 63 | Ripper Autostow SW (N/C) | Switch to Ground Input |
| 64 | Ripper Autostow SW (N/O) | Switch to Ground Input |
| 65 | Ripper Shank In / Winch Reel In | PWM Driver Switched Return |
| 66 | Ripper Shank Out / Winch Reel Out | PWM Driver Switched Return |
| 67 | LS Relief Valve | PWM Driver Switched Return |
| 68 | Quick Drop Solenoid | PWM Driver Switched Return |
| 69 | +10V Supply | Sensor Power Output |
| 70 | - Battery (4) | Battery Return |
| (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. |
| Contact Description J2(1) | ||
|---|---|---|
| No.(2) | Function | Type |
| 1 | Battery Switched | Neutral Start Input |
| 2 | Implement Lockout | Sourcing Driver Output |
| 3 | Boost Sol / Min Flow Sol | Sourcing Driver Output |
| 4 | Implement Lockout Return | Sourcing Driver Return |
| 5 | PTO Wich Press Sol / Hydraulic System Flow Sol | Sourcing Driver Return |
| 6 | XMSN Pump Bypass Sol | Sourcing Driver Return |
| 7 | A/C Clutch Coil | Neutral Start Input |
| 8 | Boost / Diverter Sol / SYS Flow / Accumulator Return | Return |
| 12 | Blower Control | Sinking Driver Output |
| 13 | Water Valve Control | Sinking Driver Output |
| 19 | Condenser Motor Relay | Sinking Driver Output |
| 20 | Backlighting / Dimming | Sinking Driver Output |
| 22 | Digital Return | Return |
| 24 | Blade Raise/Lower Position Sensor | PWM Input |
| 25 | Blade Tilt Position Sensor | PWM Input |
| 26 | Blade Angle Position Sensor | PWM Input |
| 27 | Rip Raise/Lower Position Sensor | PWM Input |
| 28 | Winch Lockout SW (N/C) | Switch to ground input |
| 29 | Winch Lockout SW (N/O) | Switch to ground input |
| 30 | Seat Belt SW (N/O) | Switch to ground input |
| 31 | Seat Belt SW (N/C) | Switch to ground input |
| 32 | Ripper In Out Sensor / Winch Y Axis | PWM Input |
| 33 | Implement Calibration Sensor | PWM Input |
| 34 | A/C Comp Discharge Press SNSR | PWM Input |
| 35 | A/C Comp Suction Press SNSR | PWM Input |
| 36 | PTO Winch High Temp | Switch to ground input |
| 37 | PTO Winch High Temp | Switch to ground input |
| 38 | Auto Ripper Control (N/C) | Switch to ground input |
| 39 | Auto Ripper Control (N/O) | Switch to ground input |
| 40 | Blower Control Feedback | PWM Input |
| 41 | Condenser Fan 2 Feedback | PWM Input |
| 42 | Main Pump Pressure SNSR | PWM Input |
| 43 | Water Valve Feedback | PWM Input |
| 44 | Winch Low Speed Lock (N/C) | Switch to Ground Input |
| 45 | Winch Low Speed Lock (N/O) | Switch to Ground Input |
| 46 | Implement Shutoff Switch (N/C) | Switch to Ground Input |
| 47 | Implement Shutoff Switch (N/O) | Switch to Ground Input |
| 50 | PTO Winch Temp | PWM Input |
| 52 | Decrement Switch (N/O) | Switch to Ground Input |
| 53 | Steering Return Filter SW / Case Drain | Switch to Ground Input |
| 58 | Blower Speed | Switch to Ground Input |
| 59 | Temp Control | Switch to Ground Input |
| 60 | Cab Pressure SNSR | Switch to Ground Input |
| 61 | PTO Accumulator Pressure SW | Switch to Ground Input |
| 64 | CAN B+ | CAN Data Link (+) |
| 65 | CAN B- | CAN Data Link (-) |
| 67 | CAN A+ | CAN Data Link (+) |
| 68 | CAN A- | CAN 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. |
| Contact Description J1(1) | ||
|---|---|---|
| No.(2) | Function | Type |
| 1 | Key Switch On | Key-On |
| 2 | XMSN Output Speed Sensor 1+ | Differential Speed Input (+) |
| 3 | XMSN Output Speed Sensor 1- | Differential Speed Input (-) |
| 4 | XMSN Output Speed Sensor 2+ | Differential Speed Input (+) |
| 5 | XMSN Output Speed Sensor 2- | Differential Speed Input (-) |
| 6 | XMSN Inter Output Speed SNSR 1+ | Differential Speed Input (+) |
| 7 | XMSN Inter Output Speed SNSR 1- | Differential Speed Input (-) |
| 8 | XMSN Inter Output Speed SNSR 2+ | Differential Speed Input (+) |
| 9 | XMSN Inter Output Speed SNSR 2+ | Differential Speed Input (-) |
| 10 | CAN Datalink + | Can Data Link (+) |
| 11 | 5V Sensor Power | +5V Sensor Supply |
| 12 | Start Relay | Sourcing Driver Output |
| 13 | -Battery (1) | Battery Return |
| 14 | Access Light Feedback | Switch to Battery |
| 15 | Torque Converter Output Speed Sensor + | Differential Speed Input (+) |
| 16 | Torque Converter Output Speed Sensor - | Differential Speed Input (-) |
| 17 | Engine Speed SNSR + | Differential Speed Input (+) |
| 18 | Engine Speed SNSR - | Differential Speed Input (-) |
| 20 | CAN Data link - | Can Data Link (-) |
| 21 | 5V Sensor Return | 5V Supply Return |
| 22 | LUC-TC Oil Temp Sensor | Analog Input |
| 23 | -Battery (2) | Battery Return |
| 24 | Ingress Lighting REQ | Switch to Battery |
| 25 | Brake Pedal Dump Switch | Switch to Battery |
| 26 | Location Code | Switch to Ground Input |
| 29 | LUC-TC Temp Sensor | Passive Analog Input |
| 31 | +Battery (1) | Battery Power Input |
| 32 | Location Code Enable | Switch to Ground Input |
| 34 | Parking Brake Switch Released (N/C) | Switch to Ground Input |
| 35 | Parking Brake Switch Engaged (N/O) | Switch to Ground Input |
| 36 | Steering Pump Charge Press SNSR | Active Analog Input |
| 37 | Lube Pressure SNSR | Active Analog Input |
| 38 | +Battery (2) | Battery Power Input |
| 39 | +Battery (3) | Battery Power Input |
| 44 | +8V Supply | Sensor Power Output |
| 45 | +8V Return | Sensor Power Return |
| 47 | +Battery | Battery Power Input |
| 48 | XMSN - Clutch 1 | Sourcing Driver Output |
| 49 | XMSN -Speed Clutch 5 | Sourcing Driver Output |
| 50 | PWM Driver Return 1-4 | Sourcing Driver Return |
| 51 | XMSN -Speed Clutch 3 | Sourcing Driver Output |
| 53 | Operator Present SNSR | Analog Input |
| 54 | PWM Driver Return 9-12 | Sourcing Driver Return |
| 56 | 10V Return | Sensor Power Return |
| 57 | - Battery (3) | Battery Return |
| 58 | Brake Proportional Sol | Sourcing Driver Output |
| 59 | XMSN -Speed Clutch 6 | Sourcing Driver Output |
| 60 | PWM Driver Return 5-8 | Sourcing Driver Return |
| 61 | XMSN -Speed Clutch 4 | Sourcing Driver Output |
| 62 | XMSN - Forward Clutch 2 | Sourcing Driver Output |
| 63 | Parking Brake Switch Released (N/C) | Switch to Ground Input |
| 64 | PTO Filter Bypass Switch | Switch to Ground Input |
| 66 | Lock Up Clutch Sol | Sourcing Driver Output |
| 67 | Left Steering Solenoid | Sourcing Driver Output |
| 68 | Right Steering Solenoid | Sourcing Driver Output |
| 69 | +10V Supply | Sensor Power Output |
| 70 | - Battery (4) | Battery Return |
| (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. |
| Contact Description J2(1) | ||
|---|---|---|
| No.(2) | Function | Type |
| 1 | Key Switch Crank | Switch to Battery Input |
| 2 | Main Power Relay Driver | Sourcing Driver Output |
| 3 | Parking Brake Dump Valve Solenoid | Sourcing Driver Output |
| 4 | Backup Alarm/ Main Power Relay Lube Flow Return | Sourcing Driver Return |
| 5 | Lube Flow Valve | Sourcing Driver Return |
| 6 | Backup Alarm | Sourcing Driver Output |
| 8 | Load Return | Sourcing Driver Return |
| 9 | Cylinder Lights Relay | Sinking Driver Output |
| 10 | Cylinder Lights Relay | Sinking Driver Output |
| 11 | Side Lights Relay | Sinking Driver Output |
| 12 | Forward ROPS Lights Relay | Sinking Driver Output |
| 13 | Rear Lights Relay | Sinking Driver Output |
| 19 | Ripper Light Relay | Sinking Driver Output |
| 20 | Push To Start Red Led | Sinking Driver Output |
| 21 | Push To Start Green Led | Sinking Driver Output |
| 22 | Digital Return | Return |
| 23 | Steering Filter Bypass Switch | Switch to Ground Input |
| 24 | Steering Position Sensor 1 | PWM Input |
| 25 | Steering Position Sensor 2 | PWM Input |
| 26 | Decel Pedal Sensor | PWM Input |
| 28 | Powered Belly Guard | Switch to Ground Input |
| 32 | Service Brake Pedal Position Sensor | PWM Input |
| 34 | Steering Motor Speed Sensor 1 | PWM Input |
| 35 | Steering Motor Speed Sensor 2 | PWM Input |
| 38 | Speed Set Recall (N/O) | Switch to Ground Input |
| 39 | Speed Set Recall (N/C) | Switch to Ground Input |
| 40 | Diff Steer Press SNSR 2 | PWM Input |
| 41 | Diff Steer Press SNSR 1 | PWM Input |
| 42 | Thumbroller Upshift/ Downshift SW | PWM Input |
| 43 | Separate Circuit Coolant Temp | PWM Input |
| 48 | FNR Position Sensor 1 | PWM Input |
| 49 | Steering Position Sensor 2 | PWM Input |
| 59 | Sep Circuit Coolant Press SNSR | Switch to Ground Input |
| 60 | PTO Level Sensor | Switch to Ground Input |
| 63 | Brake Dump Return | Load Return |
| 64 | CAN B Data Link + | CAN B HI |
| 65 | CAN B Data Link - | CAN B LOW |
| 67 | CAN Datalink A+ | CAN Data Link (+) |
| 68 | CAN Datalink A- | CAN 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. |