SECTION 4 - BASE COMPONENTS
3121222
– JLG Lift –
4-29
4.9
HYDRAULIC PUMP/MOTOR/VALVE ASSEMBLY - SERVICE PROCEDURE
Refer to Section 3.6, PUMP/LIFT/MAST - Theory of Opera-
tion for more detailed information on Pump/Motor/Valve
System.
Common Difficulties
The following difficulties can be examined using the JLG
Analyzer, a voltmeter, and simple hand tools. Unless other-
wise noted, the Control System shall be energized in
Ground Mode during testing. For a convenient Ground
Reference, place the black meter lead on the negative post
of the left battery in the left-side battery compartment.
The vehicle should be placed on a firm, level surface for all
analysis.
1. Ground Module Interlocks
There are a variety of interlocks that prevent Lift
Up due to system events (Tilted, Elevation Angle
Sensor Not Calibrated, etc). Before investigating
Pump System issues, examine the JLG Analyzer's
HELP Menu while attempting to Lift Up from
Ground Mode. Refer to Section 5 for explana-
tions of the Analyzer Help Messages.
2. Power Module Diagnostic Issues
The Power Module executes a self-test during
every power-up to ensure proper functionality.
If a Diagnostic Issue is detected, the Power Mod-
ule will not energize the Line Contactor. Instead,
it will flash the Green LED. Since these issues
may impact both the Traction and Pump Sys-
tems, please refer to the section for Power Mod-
ule Diagnostics.
3. Open-Circuit bB Terminal and Pump
Motor Positive Terminal
This issue will allow the vehicle to drive, but Lift
Up and Steer Functionality will be lost and the
Pump Motor will not operate. Under DIAGNOS-
TICS - PUMP, the JLG Analyzer will show PUMP
PWM 100% and PUMP CUR 0.0A when Lift Up is
operated from Ground Mode.
As shown in the diagram, the voltage measured
between the Pump Motor Positive Terminal and
Ground Reference should be 24V. If it is not,
examine the cable between the terminal and the
Power Module compartment. Inspect crimps for
corrosion and ensure that bolted connections
are tight. Ensure that the cable is not crushed
where it passes between the frame side sheets
and the cylinder assembly.
4. Open-Circuit between Pump Motor Negative
Terminal and P Terminal
This issue will allow the vehicle to drive, but Lift
Up and Steer Functionality will be lost and the
Pump Motor will not operate. Under DIAGNOS-
TICS - PUMP, the JLG Analyzer will show PUMP
PWM 100% and PUMP CUR 0.0A when Lift Up is
operated from Ground Mode.
After ensuring there is not an Open-Circuit
between the +B Terminal and Pump Motor Posi-
tive Terminal, check that the voltage measured
between the Pump Motor Negative Terminal
and Ground Reference is 24V. If not, examine the
issues within Open-Circuit Pump Motor. This
voltage should ramp to approximately 0V when
Lift Up is operated from Ground Mode. If not,
examine the cable between the terminal and the
Power Module compartment (P Terminal).
Inspect crimps for corrosion and ensure that
bolted connections are tight. Ensure that the
cable is not crushed where it passes between the
frame side sheets and the cylinder assembly.
5. Open-Circuit Pump Motor
This issue will allow the vehicle to drive, but Lift
Up and Steer Functionality will be lost and the
Pump Motor will not operate. Under DIAGNOS-
TICS - PUMP, the JLG Analyzer will show PUMP
PWM 100% and PUMP CUR 0.0A when Lift Up is
operated from Ground Mode.
Pull the Main Battery Disconnect to completely
de-energize the Control System. Next, detach
the cable from Pump Motor Positive Terminal.
Using a voltmeter set for resistance measure-
ment (Ohms), ensure that the resistance
between the Pump Motor Positive and Negative
Terminals is less than 2 Ohms. If not, examine
the pump motor for worn brushes or broken ter-
minals. After examination, re-connect the Pump
Motor Positive Terminal and the Main Battery
Disconnect.
6. Short-Circuit between Pump Motor Positive
and Negative Terminals
This issue will allow the vehicle to drive, but Lift
Up and Steer Functionality will be lost and the
Pump Motor will not operate. Under DIAGNOS-
TICS - PUMP, the JLG Analyzer will show an
erratic reading for PUMP PWM % and PUMP CUR
will hover around 150A when Lift Up is operated
from Ground Mode.
Pull the Main Battery Disconnect to completely
de-energize the Control System. Next, detach
both Pump Motor Terminals and insulate them
independently. Re-connect the Main Battery
Disconnect and re-try Lift Up. If the same symp-
toms persist (erratic PUMP PWM%, PUMP CUR
around 150A), examine the cabling between the
Pump Motor and Power Module compartment
for a short-circuit (most likely near area where
cylinder retracts between frame side sheets or
near pot-hole mechanism). If the symptoms
change, suspect a short-circuited (or mechani-
cally frozen) pump motor.
A clamp-on ammeter (set for 200A DC) can be
placed on either Pump Motor Cable for verifica-
tion. During Lift Up, the ammeter will read
approximately 150A.
Summary of Contents for 1230ES
Page 1: ...AS NZS Service and Maintenance Manual Model s 1230ES P N 3121222 June 22 2017 ...
Page 2: ...NOTES ...
Page 24: ...SECTION 1 MACHINE SPECIFICATIONS 1 12 JLG Lift 3121222 NOTES ...
Page 32: ...SECTION 2 GENERAL SERVICE INFORMATION 2 8 JLG Lift 3121222 NOTES ...
Page 78: ...SECTION 4 BASE COMPONENTS 4 40 JLG Lift 3121222 NOTES ...
Page 104: ...SECTION 5 CONTROL COMPONENTS 5 26 JLG Lift 3121222 NOTES ...
Page 158: ...SECTION 8 DIAGNOSTIC TROUBLE CODES 8 22 JLG Lift 3121222 NOTES ...
Page 198: ...SECTION 9 GENERAL ELECTRICAL INFORMATION SCHEMATICS 9 40 JLG Lift 3121222 ...
Page 199: ...SECTION 9 GENERAL ELECTRICAL INFORMATION SCHEMATICS 3121222 JLG Lift 9 41 ...
Page 200: ...SECTION 9 GENERAL ELECTRICAL INFORMATION SCHEMATICS 9 42 JLG Lift 3121222 ...
Page 202: ...SECTION 9 GENERAL ELECTRICAL INFORMATION SCHEMATICS 9 44 JLG Lift 3121222 NOTES ...