797B Off-Highway Truck/Tractors: Machine Electronic Control Module (Chassis)

(1) Brake/Cooling ECM. (2) Chassis ECM. (3) Transmission ECM. (4) VIMS ECM.

Electronic Control Module (ECM)

Machine Harness Connectors J1 and J2 that mate to the ECM.

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

Inputs

The machine has several input devices. The chassis 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 chassis ECM are listed in the two tables for the 70-pin connector.

Outputs

The chassis ECM sends electrical signals through the outputs. The outputs can create an action or the outputs can provide information to the chassis ECM. The outputs for the chassis 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 data link is bidirectional. The data link allows the ECM to receive information. The 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 chassis ECM is the number 087.

Table 1

Chassis ECM Contact Description J1
No. (1)	Function	Type
1	Requested Gear Command	Output
4	Machine Operation State	Sensor Input (PWM)
5	R Terminal	R Terminal
6	CAN Data Link (Low)	Input/Output
7	CAT Data Link -	Input/Output
8	CAT Data Link +	Input/Output
9	Sensor Ground Return	Ground
10	+5V Sensor Supply	Sensor Supply
11	+8V Sensor Supply	Sensor Supply
12	Sensor Ground Return	Ground
13	+12V/+10V Sensor Supply	Sensor Supply
14	Steering Accumulator Oil Pressure Sensor	Sensor Input (PWM)
18	CAN Data Link (High)	Input/Output
19	CAN Data Link (Shield)	Input/Output
20	Location Code 0	Switch Input (open/ground)
21	Location Code 1	Switch Input (open/ground)
22	Location Code 2	Switch Input (open/ground)
23	Location Code 3	Switch Input (open/ground)
25	Body Position Sensor	Sensor Input (PWM)
28	Shift Lever 5	Switch Input (open/ground)
29	Shift Lever Ground Verify	Switch Input (open/ground)
36	Shift Lever 1	Switch Input (open/ground)
37	Shift Lever 2	Switch Input (open/ground)
38	Shift Lever 3	Switch Input (open/ground)
39	Shift Lever 4	Switch Input (open/ground)
44	Hoist Screen Pressure Switch	Switch Input (open/ground)
51	Hoist Lever Sensor	Sensor Input (PWM)
57	Case Drain Hydraulic Oil Filter Switch	Switch Input (open/ground)
58	(+) 24V (Key Switch On)	Power

( 1 )

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

Table 2

Chassis ECM Contact Description J2
No. (1)	Function	Type
1	+ Battery (24V)	Power
2	- Battery	Ground
3	Hoist Control To Tank Head Solenoid	Solenoid Output
4	Hoist Pump To Control Head Solenoid	Solenoid Output
12	Return (Ground)	Solenoid Return
13	Return (Ground)	Solenoid Return
15	Steering Accumulator Charging Solenoid	Solenoid Output
16	Hoist Control To Tank Rod Solenoid	Solenoid Output
17	Hoist Pump To Control Rod Solenoid	Solenoid Output
18	Return (Ground)	Solenoid Return
22	- Battery	Ground
23	+ Battery (24V)	Power
24	Hoist Pump Bypass #1 Solenoid	Solenoid Output
25	Hoist Pump Bypass #2 Solenoid	Solenoid Output
36	Return (Ground)	Solenoid Return
38	Key Off (Key In Off Position)	Switch To Battery
39	Key Start (Key In Crank Position)	Switch To Battery
40	Body Up Lamp	Output
44	Hoist Pilot System Enable Solenoid	Solenoid Output (On/Off)
45	Accumulator Bleed Relay	Solenoid Output (On/Off)
46	- Battery	Ground
47	+ Battery (24V)	Power
49	Return (Ground)	Solenoid Return
52	Return (Ground)	Solenoid Return
55	Backup Alarm Relay	Solenoid Output (On/Off)
56	- Battery	Ground
57	+ Battery (24V)	Power
59	Return (Ground)	Solenoid Return
68	Start Relay	Solenoid Output (On/Off)
69	- Battery	Ground
70	+ Battery (24V)	Power

( 1 )

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

MARYGAR