SANY Crawler Hydraulic Excavator SY365H-9, SY365BH-9. Shop Manual (2014)

7-75

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

E-21 Incorrect boom-down pilot pressure reading

Failure information

Boom-down pilot pressure reading is incorrect.

Related information

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of 5V

power supply

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-125M

and

Voltage

About 5V

Open circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-125M

and controller pin 9

Resistance Under 1

Short circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-125M

and ground

Resistance Above 2M

Failure of sen-

sor

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-125M

and ground

Voltage

0.5V- 4.5V

CN-125M

DF-3

ZX225-1105029

Controller

Boom down
pressure sensor

Sensor GND

Sensor 5V

Signal

GND

Operator Station

Chassis harness

Fig. 7-53

7-76

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

E-22 Incorrect bucket-dig pilot pressure reading

Failure information

Bucket-dig pilot pressure reading is incorrect.

Related information

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of 5V

power supply

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-124M

and

Voltage

About 5V

Open circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-124M

and controller pin 10

Resistance Under 1

Short circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-124M

and ground

Resistance Above 2M

Failure of sen-

sor

Turn engine start switch to OFF position. Then, keep it at OFF posi-
tion to perform troubleshooting.

Between CN-124M

and ground

Voltage

0.5V- 4.5V

CN-124M

DF-3

ZX225-1105030

Controller

Bucket dig
pressure sensor

Sensor GND

Sensor 5V

Signal

GND

Operator Station

Chassis harness

Fig. 7-54

7-77

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

E-23 Incorrect bucket-dump pilot pressure reading

Failure information

Bucket-dump pilot pressure reading is incorrect.

Related information

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of 5V

power supply

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-128M

and

Voltage

About 5V

Open circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-128M

and controller pin 33

Resistance Under 1

Short circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-128M

and ground

Resistance Above 2M

Failure of sen-

sor

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-128M

and ground

Voltage

0.5V- 4.5V

CN-128M

DF-3

ZX225-1105031

Controller

Bucket dump
pressure sensor

Sensor GND

Sensor 5V

Signal

GND

Operator Station

Chassis harness

Fig. 7-55

7-78

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

E-24 Incorrect swing pilot pressure reading

Failure information

Swing pilot pressure reading is incorrect.

Related information

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of 5V

power supply

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-123M

and

Voltage

About 5V

Open circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-123M

and controller pin 18

Resistance Under 1

Short circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-123M

and ground

Resistance Above 2M

Failure of sen-

sor

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-123M

and ground

Voltage

0.5V- 4.5V

CN-123M

DF-3

ZX225-1105032

Controller

Swing pilot press. sensor

Sensor GND

Sensor 5V

Operator station

Chassis harness

Swing pilot press. sensor

Signal

GND

Fig. 7-56

7-79

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

E-25 Left travel pilot pressure reading incorrect

Failure information

Left Travel Pilot Pressure Reading is incorrect.

Related information

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of 5V

power supply

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-120M

and

Voltage

About 5V

Open circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-120M

and controller pin 34

Resistance Under 1

Short circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-120M

and ground

Resistance Above 2M

Failure of sen-

sor

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-120M

and ground

Voltage

0.5V- 4.5V

CN-120M
DF-3

ZX225-1105033

Controller

Left travel pilot
pressure sensor

Sensor GND

Sensor 5V

Signal

GND

Operator Station

Chassis harness

Fig. 7-57

7-80

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

E-26 Right travel pilot pressure reading incorrect

Failure information

Right travel pilot pressure reading is incorrect.

Related information

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of 5V

power supply

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-121M

and

Voltage

About 5V

Open circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-121M

and controller pin 30

Resistance Under 1

Short circuit of

signal line

Turn engine start switch to the OFF position before troubleshooting.
Keep it in the OFF position while troubleshooting is performed.

Between CN-121M

and ground

Resistance Above 2M

Failure of sen-

sor

Turn engine start switch to the OFF position before troubleshooting.
Turn the start switch to the ON position and keep it in the ON position
while troubleshooting is performed.

Between CN-121M

and ground

Voltage

0.5V- 4.5V

CN-121M

DF-3

ZX225-1105034

Controller

R. travel pilot press. sensor

Sensor GND

Sensor 5V

Operator station

Chassis harness

Signal

GND

R. travel pilot
press. sensor

Fig. 7-58

7-81

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

7.6 Troubleshooting Hydraulic and Mechanical Systems (H-mode)

A schematic of hydraulic and mechanical systems ...................................................... 7-82
Information contained in troubleshooting table ............................................................. 7-84
H-1 Work equipment speed slow, or swing and travel speeds slow ............................. 7-85
H-2 Engine speed drops sharply or engine stalls ......................................................... 7-86
H-3 Work equipment, swing, and travel systems do not work ...................................... 7-87
H-4 Abnormal noise in hydraulic pump ......................................................................... 7-88
H-5 Auto deceleration not functioning........................................................................... 7-88
H-6 Boom speed slow .................................................................................................. 7-89
H-7 Arm speed slow ..................................................................................................... 7-90
H-8 Bucket speed slow ................................................................................................. 7-91
H-9 Work equipment cylinders no response in separate operation ............................. 7-92
H-10 Work equipment drifts excessively ...................................................................... 7-93
H-11 Work equipment moves sluggishly ..................................................................... 7-96
H-12 Other work equipment moves while single oil circuit is relieved .......................... 7-96
H-13 Travel speed drops considerably while swinging and travelling .......................... 7-97
H-14 Machine deviates during travel ............................................................................ 7-98
H-15 Travel speed low .................................................................................................. 7-99
H-16 Machine not steered easily or steering power low ............................................. 7-100
H-17 Travel speed cannot be shifted .......................................................................... 7-101
H-18 Travel system fails (only at one side)................................................................. 7-102
H-19 Swing operation fails.......................................................................................... 7-103
H-20 Swing acceleration poor or swing speed low ..................................................... 7-105
H-21 Upper structure overrunning remarkably .......................................................... 7-107
H-22 Large shock produced upon swing stoppage .................................................... 7-108
H-23 High noise produced upon swing stoppage ....................................................... 7-109
H-24 Swing drift excessive ..........................................................................................7-110

7-82

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

A schematic of hydraulic and mechanical systems

This diagram is a simpli

cation of the diagram of the whole hydraulic system and can be referred

to in troubleshooting the hydraulic and mechanical systems.

1
2

REAR

FRONT

ZX225-1105039

L. pilot valve

R. pilot valve

Travel pilot valve

Arm

Swing

L. travel R. travel

Boom Bucket

OUT

LEFT

RIGHT

FWD

BWD

FWD

BWD

DOWN

DIG

DUMP

Accumulator

Regulator

Servo

Pilot valve

Boom priority

Bucket conflu.

Swing priority

Travel speed
change

Fig. 7-59

7-83

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

ZX225-1105040

S&S

6 6

Safety valve

Suction valve

Safety & suction valve

Arm cylinder

Standby actuating element

Swing motor

Right travel motor

Left travel motor

Boom
Cylinder

Bucket
Cylinder

Standby valve
confluence

Bucket conf-
luence valve

Arm 2 valve

Bucket
valve

Boom
valve

L. travel
valve

R. travel
valve

Straight travel
vavle

Swing valve

Boom 2

Standby
valve

Arm regener-
ation valve

Balance valve

Servo

Boom retai-

ner valve

Arm retai-

ner valve

Servo

Anti-swing

valve

Anti-swing

valve

Brake release valve

Fig. 7-60

7-84

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

Information contained in troubleshooting table

●

The following information is contained in the troubleshooting table and related electric circuit
diagrams. Fully understand these information before carrying out troubleshooting.

Failure information

Trouble which occurs on the machine

Related information

Information related to detected trouble or troubleshooting

Possible causes and standard values

Cause

Standard values and troubleshooting references

Possible causes of
trouble (Given num-
bers are reference
numbers, which do
not indicate priority)

●

< Description >

●

Standard value in normal state, which is used to judge possible
causes that might be OK or N/G.

●

A reference value is used to determine OK or N/G.

7-85

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-1 Work equipment speed slow, or swing and travel speeds slow

Failure information

●

Work equipment speed is slow or the travel and swing speeds
are slow.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Defective adjust-
ment or malfunc-
tion of main relief
valve

●

Stop the engine before troubleshooting. Perform troubleshooting while
the engine is running at high idle.

Control levers

Main relief pressure

Arm IN

33~34.3 MPa

{337~350 kg/cm

}

If normal pressure cannot be restored after adjustment, it is possible the
failure of main relief valve or internal defect. Check the valve directly.

Malfunction of
pilot relief valve

●

Stop the engine before troubleshooting. Perform troubleshooting while
the engine is running at high idle.

Control levers

Pilot control pressure

All levers in NEUTRAL

3.9~4.1 MPa

{40~42 kg/cm

}

Malfunction of
regulator

The regulator possibly fails. Check the servo mechanism of the regulator.

Malfunction of
main pump

If the trouble is caused by other factors, it might be the main pump that
has performance deterioration, malfunction or internal defect.

7-86

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-2 Engine speed drops sharply or engine stalls

Failure information

●

Engine speed drops sharply or engine stalls.

Related information

●

Information concerned

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of injection
pump

Injection pump may be defective. Check it directly.

Malfunction of
regulator

Regulator may have malfunction. Check its servo mechanism.

Clogging of oil

lter

element

Oil

lter element may be clogged. Check the element directly.

Carbon buildup at
fuel injection noz-
zle

Carbon built up at fuel injection nozzle. Check it directly.

Clogging of air
cleaner

Air cleaner may be clogged. Check it directly.

Abnormal wear of
engine

Engine may be worn abnormally. Check it directly.

7 Failure of oil pump Oil pump may be defective. Check it directly.

7-87

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-3 Work equipment, swing, and travel systems do not work

Failure information

●

Whole work equipment, swing, and travel systems do not work.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of pilot
relief solenoid valve

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Pilot lockout control lever

Pilot relief pressure

LOCKED

0 {0}

FREE

3.9~4.1 MPa

{40~42 kg/cm

}

Failure of relief valve
(pilot pump)

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Control lever

Pilot relief pressure

All levers in NEUTRAL

3.9~4.1 MPa

{40~42 kg/cm

}

Failure of hydraulic
pump

The main pump may have malfunction or internal defect. Check it by
following method.

●

Remove the oil pressure measurement plug and start the en-
gine. If oil

ows out of the opening, the piston pump is in good

condition.

4 Failure of coupling

Internal failure of the coupling can stop rotation of the pump shaft.
Check the coupling.

●

Loosen the oil delivery line of the pilot pump. If no oil is seen, it
is probably the failure of coupling.

7-88

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-4 Abnormal noise in hydraulic pump

Failure information

●

Abnormal noise is produced from the hydraulic pump

Related information

―

Possible causes and standard values

Cause

Standard values and troubleshooting references

Low level of
hydraulic oil

Make a visual check.

Inferior hy-
draulic oil

Hydraulic oil probably contains air. Make a visual check.

Clogging of
vent on top of
hydraulic tank

It is probably the clogging of the vent on top of the hydraulic tank that
causes negative pressure in the hydraulic tank. Press the release button
of the breather valve to eliminate air. Check again if the noise disappears.

Clogging of
hydraulic tank
strainer

It is probably the clogging of hydraulic tank strainer that causes negative
pressure in the oil suction line. Make a visual check.

Failure of
main pump

The main pump may have internal defect. Check the main pump.

H-5 Auto deceleration not functioning

Failure information

●

Auto-deceleration is not functioning.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Sensor fail-
ure

●

Stop the engine before troubleshooting. Perform troubleshooting while
the engine is running at high idle.

Control levers

Pilot valve output pressure

NEUTRAL

0 {0}

Operation

3.5~4.1MPa

{36~42 kg/cm2}

F a i l u r e o f
pilot valve

●

Stop the engine before troubleshooting. Perform troubleshooting while
the engine is running at high idle.

Control levers

Pilot valve output pressure

NEUTRAL

0 {0}

Operation

3.5~4.1MPa

{36~42 kg/cm

}

Controller
failure

Controller may be defective. Check it directly.

7-89

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-6 Boom speed slow

Failure information

●

The boom moves slowly.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of right
pilot valve (boom
circuit)

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Boom control lever

Pilot valve output pressure

NEUTRAL

0 {0}

Boom UP

Boom DOWN

≥

3.5MPa

{36 kg/cm2}

Malfunction of boom
control valve (spool)

Spool of boom control valve may have malfunction. Check it directly.

3 Press sensor failure

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Check the sensor by replacing it with a new one.

Malfunction of boom
control valve (retain-
ing valve)

Retaining valve of boom control valve may have malfunction. Check
the valve directly.

Malfunction or de-
fective seal of boom
control valve

(Relief valve and
makeup valve)

The relief valve and makeup valve in boom control valve may have
malfunction or defective seal. Check the valves directly.

Failure of boom
cylinder

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Charge the bucket with a load of approximate 1260 kg. Cut off the oil
passage to the high-pressure side of the cylinder. Disconnect the cyl-
inder from the main valve. Measure the displacement of piston for 15
minutes after the cylinder becomes stable. If the measured value is
greater than 10 mm, it is deemed that cylinder has a defective seal.
For more information on the measuring procedure see

"Hydraulic

Drift of Work Equipment - Test" on page 6-34.

7-90

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-7 Arm speed slow

Failure information

●

The arm moves slowly.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of left
pilot valve (arm
circuit)

●

Stop the engine before troubleshooting. Perform troubleshooting while
the engine is running at high idle.

Arm control lever

Pilot valve output pressure

NEUTRAL

0 {0}

Arm IN or Arm OUT

≥

3.5MPa

{36 kg/cm

}

2 Press sensor failure

●

Stop the engine before troubleshooting. Perform troubleshooting while
the engine is running at high idle.

Check the sensor by replacing it with a new one.

Malfunction of arm
control valve (spool)

Spool of arm control valve may have malfunction. Check it directly.

Malfunction of arm
control valve (re-
generation valve)

Regeneration valve of arm control valve may have malfunction.

Check it directly.

Malfunction or de-
fective seal of arm
control valve (Relief
valve and makeup
valve)

The relief valve or makeup valve inside the arm control valve may have
malfunction or defective seal. Check the valves directly.

Failure of arm cylin-
der

●

Stop the engine before troubleshooting. Perform troubleshooting while
the engine is running at high idle.

Cut off the oil passage to the high-pressure side of the cylinder. Discon-
nect the cylinder from the main valve. Measure the displacement of piston
for 15 minutes after the cylinder becomes stable. If the measured value is
greater than 10 mm, it is deemed that cylinder has a defective seal. For
more information on the measuring procedure see

"Hydraulic Drift of

Work Equipment - Test" on page 6-34.

SANY Crawler Hydraulic Excavator SY365H-9, SY365BH-9. Shop Manual (2014) - page 27