797B Off-Highway Truck: Solenoid Valves & Relays

Hoist Pump Bypass (1) Solenoid Valve

Hoist Pump Bypass (2) Solenoid Valve

Hoist Pilot ON/OFF Solenoid Valve

Hoist Rod End Control To Tank Proportional Solenoid Valve

Hoist Head End Control To Tank Proportional Solenoid Valve

Hoist Rod End Pump To Control Proportional Solenoid Valve

Hoist Head End Pump To Control Proportional Solenoid Valve

Hoist Control Valve (1) Hoist pump bypass (2) solenoid valve (2) Hoist pump bypass (1) solenoid valve. (3) Hoist pilot ON/OFF solenoid valve. (4) Hoist rod end control to tank proportional solenoid valve. (5) Hoist head end control to tank proportional solenoid valve. (6) Hoist rod end pump to control proportional solenoid valve.(7) Hoist head end pump to control proportional solenoid valve.

Solenoid Valve

The hoist solenoids are used to control the flow of oil to and from the hoist cylinders. All of the solenoids except the hoist pilot enable solenoid are controlled proportionally. The proportional control allows the operator to modulate the oil flow to and from the hoist cylinders.

The following table shows the state of the hoist solenoids during various typical operating conditions. The actual amount that the solenoids turn on depends on the amount of modulation requested by the operator and the state of the machine.

Table 1

Condition Of Hoist System (Typical Example)	State Of Hoist Solenoids
	Pilot Enable	BP 1	BP 2	CTHE	CTRE	PCHE	PCRE
Hold (hoist lever just moved into HOLD)	ON	OFF	OFF	OFF	OFF	OFF	OFF
Hold (hoist lever has been in HOLD for a while)	OFF	OFF	OFF	OFF	OFF	OFF	OFF
Raise with cylinders in first stage	ON	ON	ON	OFF	ON	ON	OFF
Raise with cylinders in second stage	ON	ON	ON	OFF	OFF	ON	OFF
Float (Hoist System Configuration "0")	ON	ON	ON	ON	OFF	OFF	ON
Float (Hoist System Configuration "1" or "2")	ON	OFF	OFF	ON	ON	ON	ON
Lower with cylinders in second stage	ON	ON	ON	ON	OFF	OFF	ON

Table 2

BP 1 = Pump Bypass 1

BP 2 = Pump Bypass 2

CTHE = Control to Tank Head

CTRE = Control to Tank Rod

PCHE = Pump to Control Head

PCRE = Pump to Control Rod

The hoist pump bypass (1) solenoid and hoist pump bypass (2) solenoid are outputs of the ECM. The hoist pump bypass (1) solenoid connects to the ECM at connector contact J2-24. The hoist pump bypass (2) solenoid connects to the ECM at connector contact J2-25.

The hoist rod end control to tank proportional solenoid is an output of the ECM. The hoist rod end control to tank proportional solenoid connects to the ECM at connector contact J2-16.

The hoist head end control to tank proportional solenoid is an output of the ECM. The hoist head end control to tank proportional solenoid connects to the ECM at connector contact J2-3.

The hoist rod end pump to control proportional solenoid is an output of the ECM. The hoist rod end pump to control proportional solenoid connects to the ECM at connector contact J2-17.

The hoist head end pump to control proportional solenoid is an output of the ECM. The hoist head end pump to control proportional solenoid connects to the ECM at connector contact J2-4.

The hoist pilot ON/OFF solenoid is an output of the ECM. The hoist pilot ON/OFF solenoid connects to the ECM at connector contact J2-15.

Note: The ECM diagnoses certain failures in the circuit of the hoist control valve. The ECM will detect a diagnostic code when an electrical problem with the wiring or solenoid is detected. This diagnostic code is displayed on the message display. See System Operation, "Diagnostic Operation". The status of the solenoids are also available to other modules through the CAT data link.

The solenoids have a connector with two contacts. The solenoid receives +battery voltage from the ECM through contact 1. The solenoid receives ground from the ECM through contact 2.

Solenoid Valve (Air Start)

Solenoid (Air Start)

The air start solenoid valve is an output of the ECM. The air start solenoid valve connects to the ECM at connector contact J2-68. The solenoid activates the starting of the engine. This solenoid is part of the neutral start function. See Systems Operation, "Neutral Start Function" for more information. The ECM activates the solenoid with +battery voltage and the solenoid is deactivated when the +battery voltage is not supplied. The air start solenoid valve turns the flow of air to the starting motor ON and OFF.

The solenoid has a connector with two contacts. Contact 1 connects to the ECM and the contact receives +battery voltage in order to activate the solenoid. Contact 2 connects to the ECM to return ground.

The ECM records diagnostic codes that occur with the air start solenoid valve. A diagnostic code that occurs with the air start solenoid valve is recorded as a CID 0444.

Relays

Relay

Backup Alarm Relay

The relay for the backup alarm is an output of the ECM. The relay connects to the connector contact J2-55. The relay controls the backup alarm and the backup alarm lamps. The backup alarm alerts personnel that the machine is backing up. See the topic System Operation, "Backup Alarm Function". When the operator selects REVERSE, the ECM sends a +battery signal to the relay. When the relay is activated, +battery voltage is applied to the backup alarm.

The relay has five terminals. The terminal "85" receives the +battery signal from J2-55 from the ECM. The terminal "86" is connected to frame ground through J2-36 of the ECM. The terminal "30" connects to a +battery source. The terminal "87" connects to the backup alarm. The terminal "87a" is not used.

Steering Relay And Brake Accumulator Relay

The relay for the steering accumulator and the brake accumulator is an output of the ECM. The relay connects to the connector contact J2-45. See the topic System Operation, "Accumulator Bleed Down Function".

The relay has five terminals. The terminal "85" receives the +battery signal from J2-45 from the ECM. The terminal "86" is connected to frame ground through J2-3 of the ECM. The terminal "30" connects to a +battery source. The terminal "87" connects to the steering accumulator bleed down solenoid and the brake accumulator bleed down solenoid. The terminal "87a" is not used.

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797B Off-Highway Truck: Solenoid Valves & Relays 2012-12-25T18:29:00-08:00 Rating: 4.5 Diposkan Oleh: Unknown