312F and 313F Excavator Machine Systems Electronic Control (Machine System) Caterpillar

Electronic Control Module (ECM)

Illustration 1	g02612416
Machine ECM (1) Controller (2) J2 Connector (3) J1 Connector

Illustration 2	g06195503
Connectors of Machine ECM (2) J2 Connector (3) J1 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 54-pin connectors (J1 and J2). The inputs and outputs to the ECM can be viewed through the AVSpare 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 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.

Pin Locations

The Cat Data Link is used to provide a connection for the service tool for troubleshooting, testing, and calibrations. The data link is bidirectional. The data link allows the ECM to receive information. The data link also allows the ECM to send information.

Table 1

Machine ECM Connector J1 Contact Descriptions(1)
No.	Type	Pin Description
1	Power	+Battery
2	Ground	Ground
3	Output	Swing Brake Solenoid
4	Input	Boom Angle Sensor
5	Input	Stick Angle Sensor
8	Power	Power Supply for Potentiometer 5V
11	Input	Left J/S Switch 1 (Upper)
12	Input	Left J/S Switch 2 (Fore)/Intelligent Hammer Enable Switch
13	Power	+Battery
14	Ground	Ground
16	Input	Boom Up Control Pressure Sensor for Tool Control System
17	Input	Boom Down Control Pressure Sensor
18	Ground	Analog Return
19	Input	ATT Stem 3 Status
20	Input	ATT Stem 4 Status
21	Input	Right J/S Switch 1 (Upper)
22	Input	Right J/S Switch 2 (Fore)
23	Input	Key Switch
24	Power	Power Supply for Sensor 24V
25	Output	Travel Speed Change Solenoid
26	Input	Stick In Control Pressure Sensor for TCS / UQC
27	Power	Power Supply for Sensor (8V)
28	Input	Squeeze Sensor for TCS
31	Input	Implement Pressure Switch
32	Input	Bucket Pressure Switch for Crane
33	Output	Hydraulic Lock Solenoid
34	Input	Stick Out Control Pressure Sensor for TCS
35	Input	Swing Control Pressure Sensor
36	Input	Boom Cylinder Head Pressure Sensor
37	Input	Boom Cyl Rod Press Sensor for Crane / SMTBM
38	Input	AUX Pedal 2 Control Pressure Sensor / ATT L Pedal
39	Input	Straight Travel Pressure Switch
40	Input	One Touch Low Idle Switch
41	Input	Foot Switch
42	Input	Tool 10 Detect Status
44	Input	Bucket PSC
45	Input	AUX Pedal 1 Control Pressure Sensor / ATT R Pedal
46	Input	Bucket Cylinder Head Pressure Sensor
47	Input	Stick Angle PWM Sensor
48	Input	Negative Flow Control 1 Pressure Sensor
49	Input	Negative Flow Control 2 Pressure Sensor
51	Input	Thumb Wheel - LH/Left J/S Switch 4
50	Input	Boom Angle PWM Sensor
52	Input	Thumb Wheel - RH/Right J/S Switch 4
53	Input	Drive Pump Pressure Sensor
54	Input	Idler Pump Pressure Sensor

(1)	Contacts that are not listed are not used.

Table 2

Machine ECM Connector J2 Contact Descriptions(1)
No.	Type	Pin Description
1	Output	ATT Stem 1 Extend EPRV / REPRV for TCS
2	Output	ATT Line 1 REPRV
3	Output	ATT Stem 2 Retract EPRV / REPRV for TCS
4	Output	ATT Stem 2 Extend EPRV / REPRV for TCS
8	Output	Power Shift Pressure EPRV
9	Output	Boom Regeneration REPRV
11	Input	Boom 2 Up REPRV
13	Output	ATT Stem 1 Retract EPRV / REPRV for TCS
16	Input/Output	AVS Data Link - (Speed Sensor Spare)
19	Ground	PRV Return
21	Ground	PRV Return
22	Ground	PRV Return
23	Output	ATT Line 2 REPRV
24	Input	Drive Pump Displacement Sensor
25	Input/Output	AVS Data Link + (Speed Sensor Spare)
27	Input	Hydraulic Lock Cancel Switch
29	Output	Boom Up Limit REPRV
31	Output	ATT Stem 3 Extend EPRV
34	Output	ATT Stem 3 Retract EPRV
38	Output	Bucket Out Limit EPRV
39	Output	Boom Down REPRV for TCS / E-FENCE / SMTBM (S1)
40	Output	Stick In REPRV for TCS
41	Output	Stick Out REPRV for TCS
43	Output	Negative Flow Control 2 Limit EPRV
45	Input/Output	ATCH CAN (J1939) Data Link +
46	Input/Output	ATCH CAN (J1939) Data Link -
47	Input/Output	CAN (J1939) Data Link +
48	Input/Output	CAN (J1939) Data Link -
50	Input/Output	Machine CAN Data Link +
51	Input/Output	Machine CAN Data Link -
53	Output	Negative Flow Control 1 Limit EPRV
54	Input	Idler Pump Displacement Sensor

Illustration 3	g02655338
Underside of Soft Switch Panel

Table 3

Switch Panel Connector J1 Contact Descriptions(1)
No.	Type	Pin Description
2	Input	Fuel Level Sensor
3	Input	Hydraulic Oil Temperature Sensor
4	Ground	Analog Return
5	Output	A/C Unit
7	Input	Refuel Start Switch
8	Input	Capsule Filter Switch Plugged
9	Input	Fine Swing Switch
10	Input	Hydraulic ATT Filter Plugged Switch
11	Input	Overload Warning Alarm Enable Switch
12	Input	Water Separator Level Switch
13	Input	Boom Low Pressure Relief Enable Switch
15	Input	Crane Cancel Switch for Crane

Table 4

Switch Panel Connector J2 Contact Descriptions (1)
No.	Type	Pin Description
1	Input/Output	Machine CAN Data Link +
2	Input/Output	Machine CAN Data Link -
4	Output	Washer
5	Output	Wiper Intermittent 3
6	Output	Wiper Intermittent 6
7	Output	Wiper Low

Table 5

Switch Panel Connector J3 Contact Descriptions(1)
No.	Type	Pin Description
1	Power	+Battery
2	Ground	Ground
3	Input	Key Switch 1
4	Output	Quick Coupler Hold to Run Solenoid
5	Output	Quick Coupler Bypass Cut Solenoid
6	Output	Fine Swing Solenoid
7	Output	Heavy Lift Solenoid (If equipped)
8	Output	Caution Lamp for Crane
9	Output	Boom Down ELE Check Solenoid for Smart Boom (EC1)
11	Output	Boom Up ELE Check Solenoid for Smart Boom (EC2)
12	Output	Travel Alarm
13	Output	Quick Coupler Uncoupling Solenoid
15	Output	Chassis/Cab Light Relay
16	Output	Boom Light Relay
17	Output	Refuel Pump Relay
19	Output	Alternator R Terminal (P Terminal)
20	Input	Quick Coupler Unlock Switch

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 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:

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.

Sensors

Low Pressure Sensors

Illustration 4	g02263393

Note: The values in Table 6 are for bench testing only. Values may not represent parameters for machine systems specifications.

Table 6

Operating Pressure	10 MPa
Supply Voltage	+7V ~ +14V
Output Signal	500 ± 100 Hz (PWM)
Output Range	5% ~ 95%

The low-pressure sensors include:

• Boom Down Control Pilot Pressure Sensor

• Negative Flow Control 1 Pressure Sensor

• Negative Flow Control 2 Pressure Sensor

High Pressure Sensors

Illustration 5	g02263513

Note: The values in Table 7 are for bench testing only. Values may not represent parameters for machine systems specifications.

Table 7

Operating Pressure	50 MPa
Supply Voltage	+7V ~ +14V
Output Signal	500 ± 100 Hz (PWM)
Output Range	5% ~ 95%

The high-pressure sensors include:

• Pump 1 Pressure Sensor (drive pump)

• Pump 2 Pressure Sensor (idler pump)

Hydraulic Oil Temperature Sensor

Illustration 6	g03344952

Note: The values in Table 8 are for bench testing only. Values may not represent parameters for machine systems specifications.

Table 8

Constant Voltage	Temperature	Restance (Ohms)
12V DC	0° C (32° F)	3268 Ω
	25° C (77° F)	1000 Ω
	35° C (95° F)	653 Ω
	50° C (122° F)	360 Ω
	75° C (167° F)	148 Ω
	100° C (212° F)	68 Ω
	125° C (257° F)	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.

Switches

Pressure Switch

Illustration 7	g02332474

Note: The values in Table 9 are for bench testing only. Values may not represent parameters for machine systems specifications.

Table 9

Activation Pressure	490 ± 49 kPa (71 ± 7 psi)
Deactivation Pressure	294 kPa (43 psi) MIN
Rating	+ 12V ~ +32V 0.01 Amp to 1 Amp
Pressure Range	0 to 10 MPa

The pressure switches include:

• Implement pressure switch

• Travel pressure switch

Hydraulic Oil Filter Switch

Illustration 8	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.

One Touch Low Idle Switch

Illustration 9	g02655636
Standard Right Joystick (1-Button) (1) One Touch Low Idle Switch (2) One Touch Low Idle Switch Connections

Illustration 10	g02658859
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 10.

The one touch low idle switch (1) is located on the top or on the front of the right joystick (see Illustrations 9 and 10). 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.

Horn Switch

Illustration 11	g03230240
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.

Right Side Control Panel

Note: Your machine may not be equipped with all of the controls that are described in this topic.

Illustration 12	g02774877
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.

Illustration 13	g02160606
High Power Mode

Illustration 14	g02160607
Standard Power Mode

Illustration 15	g02160612
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.

Key Start Switch

Illustration 16	g06024458
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.

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.

Outputs

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.

Solenoids

On/Off Solenoids

Illustration 17	g01158530

Note: The values in Table 10 are for bench testing only. Values may not represent parameters for machine systems specifications.

Table 10

Rated Voltage	24 VDC
Coil Resistance	41.5 ± 2.0 Ω (T=20° C)

The On/Off solenoid in Illustration 17 includes:

• Swing brake solenoid

• Travel speed solenoid

• Hydraulic lock solenoid

Proportional Reducing Solenoid Valve

Illustration 18	g02703776

Note: The values in Table 11 are for bench testing only. Values may not represent parameters for machine systems specifications.

Table 11

Current Range	0 mA ~ 700 mA
Coil Resistance	15.0 ± 0.7 Ω (T=20° C)

Illustration 19	g02263554
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:

• Power Shift Pressure PRV

Reverse Proportional Reducing Solenoid Valve

Illustration 20	g02304374
Valve cutaway, hydraulic schematic symbol, and electrical connector designation

Note: The values in Table 12 are for bench testing only. Values may not represent parameters for machine systems specifications.

Table 12

Current Range	0 mA ~ 700 mA
Coil Resistance	15.0 ± 0.7 Ω (T=20° C)

Illustration 21	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

Data Link

Cat Data Link

Illustration 22	g02694217
Schematic of the “Cat Data Link” Circuit

The Cat Data Link is an input and an output of the Machine ECM. The Cat Data Link connects to the Machine ECM at connector contact J2-16 and J2-25. The data link is designed to carry communications between the controller and the monitor. The data link is not a visible component. The data link consists of internal control circuits and a harness wiring. The data link is bidirectional. The controller can receive information and the controller can send information through the data link. The controller sends information about the fuel level, temperature of the engine coolant, and many other signals to the monitor panel.

CAN Data Link

Illustration 23	g06024714
Schematic of the "CAN Data Link" Circuit

The CAN data link is used for communication between the following modules: Machine ECM, Switch Panel and Monitor. Two 120 Ohm terminating resistors must be installed in the wiring harness in order for the CAN data link to function properly.

Action Alarm

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.

Travel Alarm

The travel alarm SOUNDS in order to alert the area that the machine is moving.