TUBE AS 2804417 - Caterpillar

Engine Electronic Control Module (ECM)
Illustration 1 g06073349
Engine ECM
(1) Engine ECM
(2) J1 Connector
(3) J2 Connector
Illustration 2 g06073374
Connector of Engine ECM
(2) J1 Connector
(3) J2 ConnectorThe engine ECM bases decisions on input information and memory information. After the ECM receives the input information, the ECM sends a corresponding response to the outputs. The inputs and outputs of the engine ECM are connected to the engine harness by two 86 contact connectors (J1 and J2). The inputs and outputs to the ECM can be viewed through the Caterpillar Electronic Technician (Cat ET).Note: Only the complete ECM is serviced (no lower-level components). The ECM must be replaced if the ECM is damaged. Replace the ECM if a failure is diagnosed.Pin Locations
Table 1
Engine ECM Connector J1 Contact Descriptions(1)
No. Type Pin Description
4 Output Fan Solenoid
75 Input Fan Reverse Switch
(1) Contacts that are not listed are not used.Inputs
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 and 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: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.Insome cases, the operator is provided a manual switch that can be used to change a condition of the machine.Outputs
On/Off Solenoids
Illustration 3 g01158530Note: The values in Table 2 are for bench testing only. Values may not represent parameters for machine system specifications.
Table 2
Rated Voltage 24 VDC
Coil Resistance 8.7 0.4 Ω (T=25°C) Data Link
CAN Data Link
A Controller Area Network (CAN) Data Link allows communication between the Machine ECM, Engine ECM, and the input and output devices of the switch panel. The CAN Data Link allows for bi-directional electronic signals to be passed among the controllers and the switch panel. The data link allows the Machine ECM to be connected to sensors and actuators connected to the switch panel. The Machine ECM can also use the data link to communicate engine speed and/or torque requirements to the Engine ECM.