621H, 623H and 627H Wheel Tractor-Scrapers Implement Electronic Control System Caterpillar

Electronic Control Module (ECM)

Usage:

623H DBF

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Illustration 1	g00554751
Electronic Control Module (ECM)

The ECM makes decisions based on the information from inputs and information from memory. After the ECM receives the information from inputs and information from memory, the ECM will send a corresponding response through the outputs. The inputs and outputs of the ECM connect to the machine harness by two 70-pin connectors (J1 and J2).

Inputs

The machine has several input devices. The ECM receives information from components about machine operations. The machine has switch-type inputs and sensor-type inputs. 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 a signal to the ECM that constantly changes. The inputs to the ECM are listed in the two tables for the 70-pin connector.

Outputs

The Implement ECM sends electrical signals through the outputs. The outputs can create an action or the outputs can provide information to the Implement ECM. The outputs for the Implement ECM are listed in the two tables for the 70-pin connector.

Input/Output

Each ECM uses the Cat Data Link to communicate with each other. The Cat Data Link is bidirectional. The Cat Data Link allows the ECM to receive information. The Cat Data Link allows the ECM to send information. The data link allows the sharing of information with other electronic control modules.

A module identifier (MID) is assigned to each ECM. The MID for the Implement ECM is the number 082.

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Table 1
Implement ECM Contact Description J1
No. ⁽¹⁾	Function	Type
1	Key Switch	Switch Input
10	Cat Data Link +	Input/Output
12	Pilot Solenoid	Proportional Output
13	-Battery	Ground
14	A/C Switch (Manual Mode)	Switch Input
20	Cat Data Link +	Input/Output
22	Hydraulic Oil Temp Sensor	Sensor Input
23	- Battery	Ground
24	A/C Refrigerant Switch	Switch Input
25	A/C Switch (Auto Mode)	Switch Input
27	ECM Location 1	Switch Input (Open / Ground)
29	HVAC Outlet Temp Sensor	Sensor Input
30	Evaporator Temperature Sensor	Sensor Input
31	+24V Battery	Power
32	ECM Location Enable
33	Elevator Charge Pump Filter Bypass Switch	Switch Input (Open / Ground)
34	Elevator Motor Case Drain Filter Bypass Switch	Switch Input (Open / Ground)
35	Grade Control/Load Assist Switch (N/O)	Switch Input (Open / Closed)
37	A/C Operator Temperature Control	Resistive Sensor Input
38	+24V Battery	Power
40	Grade Control / Load Assist SW (N/C)	Switch Input (Closed / Open)
41	Sequence Assist Mode SW (N/O)	Switch Input (Open / Closed)
42	Sequence Assist Mode SW (N/C)	Switch Input (Closed / Open)
44	+8V Sensor Supply	Power
45	+8V Sensor Return	Ground
46	+24V Battery	Power
48	Bowl Raise Solenoid 1	Proportional Output
49	Bowl Lower Solenoid 1	Proportional Output
50	Driver Return 1 - 4	Ground
51	Ejector Forward Solenoid	Proportional Output
52	Ejector Reverse Solenoid	Proportional Output
53	A/C Cab Temperature Sensor	Sensor Input
54	Driver Return 11 - 12	Ground
55	Driver Return 9 - 10	Ground
56	+10V Sensor Return	Ground
57	-Battery	Ground
58	Apron Raise Solenoid	Proportional Output
59	Apron Lower Solenoid	Proportional Output
60	Driver Return 5 - 8	Ground
61	Bowl Raise Solenoid 2	Proportional Output
62	Bowl Lower Solenoid 2	Proportional Output
63	Cushion-Hitch SW (N/O)	Switch Input (Open / Closed)
64	Cushion-Hitch SW (N/C)	Switch Input (Closed / Open)
66	Cushion Hitch Solenoid	Proportional Output
67	Elevator Forward Solenoid	Proportional Output
68	Elevator Reverse Solenoid	Proportional Output
69	+10V Sensor Supply	Power
70	Active Analog Sensor Return	Ground

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The connector contacts that are not listed are not used. The connector has 70 contacts.

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Table 2
Implement ECM Contact Description J2
No. ⁽¹⁾	Function	Type
2	Bail Solenoid	Output (On/Off)
3	Camera Trigger - Cutting Edge	Switch Output
4	On/Off Driver Return 1 - 3	Ground
5	Camera Trigger - RR	Switch Output
6	Camera Trigger - RH	Switch Output
8	On/Off Driver Return 4 - 6	Ground
10	Rear Wiper On / Off Relay	Output (On/Off)
12	Rear Wiper High / Low Relay	Output (On/Off)
13	Rear Washer Relay	Output (On/Off)
17	Apron Position Sensing Cylinder	Sensor Input
18	Bowl Position Sensing Cylinder	Sensor Input
19	A/C Compressor Clutch Relay	Output (On/Off)
20	Condenser Relay	Output (On/Off)
21	Water Valve Actuator	Proportional Output
22	Switch Return	Ground
24	Implement Control Lever Position Sensor - Bowl	Sensor Input
25	Implement Control Lever Position Sensor - Ejector	Sensor Input
26	Implement Control Lever Position Sensor - Apron / Elevator	Sensor Input
30	Implement Lockout Switch (N/O)	Switch Input (Open / Closed)
31	Implement Lockout Switch (N/C)	Switch Input (Closed / Open)
32	Ground Speed Radar	Sensor Input
34	Ejector Cylinder Head End Pressure Sensor	Sensor Input
35	Ejector Cylinder Rod End Pressure Sensor	Sensor Input
36	WAVS Camera Scroll Switch	Switch Input
37	WAVS Camera Scroll Parity Switch	Switch Input
38	WAVS Camera Set Switch	Switch Input
39	WAVS Camera Set Parity Switch	Switch Input
50	Calibration Pressure Sensor	Service Tool Sensor Input
52	Bail Raise SW (N/O)	Switch Input (Open / Closed)
53	Bail Raise SW (N/C)	Switch Input (Closed / Open)
56	CAN A Datalink +	Input / Output
58	Elevator Pump Case Drain Filter Bypass SW	Switch Input (Open / Ground)
59	Implement Pilot Pressure Filter Bypass SW	Switch Input (Open / Ground)
63	Passive Analog Sensor Return	Ground
64	CAT Grade Control Data Link +	Input / Output
65	CAT Grade Control Data Link -	Input / Output
67	CAN A Datalink +	Input / Output
68	CAN A Datalink -	Input / Output
70	CAN A Datalink -	Input / Output