Turntable Sensor Faulted; Eeprom Checksums Failure; Backward Stability Concern Message; Forward Stability Concern Message - JLG 740A Service And Maintenance Manual

Turntable Sensor Faulted

8/1 TURNTABLE FAULTED
If the system detects that the Chassis tilt sensor frequency
outside the 100Hz +/- 5Hz range or the duty cycle is out-
side 50% +/- 21% range the control system shall report a
fault
Solution:
• Inspect wire harness going to the sensor and UMS
module.
• Inspect sensor mounting.
• Replace sensor.

EEPROM checksums failure

9/9 EEPROM FAILURE – CHECK ALL SETTINGS
A critical failure occurred with the EEPROM. Personalities,
machine configuration digits, etc. may be reset to default
values and should be checked.
Solution:
• Contact JLG if message is reoccurring.
4.18 UMS TROUBLESHOOTING AND FAULT
MESSAGES - ADE MACHINES

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
will be disallowed immediately. Tower Lift Down will 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 will light/
sound continually and a fault shall be raised. These condi-
tions will 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.
3121160
SECTION 4 - BOOM & PLATFORM

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 control
boom malfunction indicator lamp, the platform malfunc-
tion indicator lamp, and platform alarm will light/sound
continually and a fault will be raised. The light/alarm signal
will stop 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.

Auto Detection Input Low Message

2/5 AUTO DETECTION INPUT LOW
If the UMS detects a valid ground module software version
but digital input 2 is not tied high the UMS module shall
report a fault.
Solution:
• Inspect wire harness, there should be 12 volts going
into pin J1-5 (black connector) of UMS module.

UMS Sensor Communications lost

6/6 UMS SENSOR COMMUNICATIONS LOST
If the UMS detects a valid ground module software version
but digital input 2 is not tied high the UMS module shall
report a fault.
Solution:
• Inspect wire harness; CANbus communications are on
pins J2-9 & J2-10 (gray connector) of the UMS module.
• Using access level 1 of the UMS module, under "DIAG-
NOSTICS" CAN, RX/SEC and TX/SEC should be val-
ues greater than 0. Also "BUS OFF:" and "BUS ERR:"
should be 0 and "PASSIVE:" should be a low value.
– JLG Lift – 4-65