JLG 740AJ, Service And Maintenance Manual

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SECTION 4 - BOO M & PLATFOR M
4-66 3121160
4.18 UMS TROUBLESHOOTING AND FAULT MESSAGES
NON-ADE MACHINES
Tower Lift Down Permanently closed
2/2 FUNCTION LOCKED OUT - TOWER LIFT DOWN PERMANENTLY
CLOSED.
The control system shall illuminate lamps and sound the alarm at
startup for one second on and one second off. If the control sys-
tem detects the TOWER LIFT DOWN, it shall report a fault. The
TOWER LIFT DOWN function shall be locked out and activate the
ground boom malfunction indicator lamp, upright tilted lamp
and platform alarm continually until the condition is cleared.
Solution:
• Inspect switch and harness. Voltage (

12V) should only be
present on J1-3 of the UMS module when Tower Down
switch is closed.
Backward Stability Concern Message
2/5 UMS SENSOR BACKWARD LIMIT REACHED.
When the upright angle relative to the turntable is higher than
+2.5° (away from the work platform), tower lift down shall be dis-
allowed immediately. Tower Lift Down shall be re-allowed when
the upright angle relative to the turntable is less than 2.0

. If
Tower Lift Down is disabled for more than 1.5 seconds, the
ground boom malfunction indicator lamp, upright tilted lamp
and platform alarm shall light/sound continually and a fault shall
be raised. These conditions shall be latched along with Tower Lift
Down until the upright angle is less than 2.0

for 2 seconds and
the Tower Lift Down command is returned to neutral.
Solution:
• Inspect sensor mounting.
• Verify sensor calibration on level pad.
• Follow the corrective action listed on decal 1702265
located near the red knob of the machine.
• Inspect machine hydraulics.
Forward Stability Concern Message
2/5 UMS SENSOR FORWARD LIMIT REACHED.
When the upright angle relative to the turntable is less than –4.0°
for longer than 1.5 seconds, the ground boom malfunction indi-
cator lamp, the platform distress lamp, and platform alarm shall
light/sound continually and a fault shall be raised. The light/
alarm signal shall be removed only when the upright angle
reaches values greater than –3.0° for 2 seconds.
Solution:
• Inspect sensor mounting.
• Verify sensor calibration on level pad.
• Tower lift down.
• Inspect machine hydraulics.
UMS Out of Usable Range Message
2/5 UMS SENSOR OUT OF USABLE RANGE
When both the Turntable tilt sensor and the UMS sensor read
greater then

10

in the same direction the UMS shall be disen-
gaged until the condition no longer exists and a fault shall be
raised.
Solution:
• Verify the message clears when operating the machine on
grade less than 10

.
• Inspect sensor mounting.
• Verify sensor calibration on level pad.
Battery Voltage < 9.0 Volts
4/4 SYSTEM VOLTS LOW
Battery voltage is below 9V.
Solution:
• Inspect battery and alternator output.
• Inspect harness, looking closely for possible short circuits.
Battery Voltage > 16.0 Volts
4/4 SYSTEM VOLTS HIGH
Battery voltage is above 16V.
Solution:
• Inspect battery and alternator output.