JLG 800A_AJ ANSI Service Manual - Manual (Page 276)

SECTION 4 - BOOM & PLATFORM
4-62 – JLG Lift – 3120740
4.17 UMS TROUBLESHOOTING AND FAULT
MESSAGES - NON-ADE MACHINES
Tower Lift Down Permanently closed
2/2 FUNCTION LOCKED OUT - TOWER LIFT DOWN PER-
MANENTLY CLOSED
The control system shall illuminate lamps and sound the
alarm at startup for one second on and one second off. If
the control system 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 con-
tinually 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 disallowed 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 condi-
tions 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 indicator 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 disengaged 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 cir-
cuits.
Battery voltage > 16.0 Volts
4/4 SYSTEM VOLTS HIGH
Battery voltage is above 16V.
Solution:
• Inspect battery and alternator output.