JLG 3246ES Service Manual - Manual (Page 126)

SECTION 5 - JLG CONTROL SYSTEM
5-6 – JLG Lift– 3121166
trol box carefully. Observe whether the tilt sen-
sor is properly seated.
c. Tilt sensor has developed an offset shift:
Remove the tilt sensor from the Ground Con-
trol box but keep both the tilt sensor and
Ground Control box electrically connected.
Level one axis of the tilt sensor and observe
the raw reading (should be within ± 2.0). Do
the same for the other axis. If either axis is
greater than ± 2.0, replace the tilt sensor.
NOTE: Check that the tilt switch is properly set by referring
to the Tilt Settings table in section 1 of this manual.
Failure Troubleshooting for The Field
Some possible reasons that the tilt sensor will not cali-
brate are:
a. The surface the machine is sitting on is off level
by a few degrees (flat doesn’t imply level; park-
ing lots are often not level).
b. The tilt sensor has failed one or both of the
channels (X axis and Y axis).
c. Tilt sensor has moisture intrusion that has
shifted its output.
d. Water and/or corrosion in the box has cor-
rupted electrical connections or caused a tilt
s e n s o r o r g ro u n d c o nt ro l b o a rd f a i l u re
(observe any cracks in the box).
e. The Ground Control Box, as mounted on the
machine, does not allow the tilt sensor to be
level.
For the following troubleshooting steps, a bubble level
(smaller is better) will be needed and the machine must
be on a level surface:
1. On the Analyzer, go to the Diagnostics/System and
read the tilt angle. If either angle reports +20.0°,
there is an electrical/electronic failure (tilt sensor,
control board, electrical connections).
a. Take the Ground Control box off of the
machine and open the rear cover.
b. Disconnect the sensor and clean any corrosion
off of the tilt sensor and control board connec-
tions.
c. Reassemble and test. If fault persists, replace
tilt sensor.
2. If the Analyzer displays angles other than +20.0°,
attempt to calibrate. If machine won’t calibrate,
note the reason displayed on Analyzer:
a. SENSOR FAILURE – tilt sensor internal fre-
quency is out of range (replace sensor).
b. NOT LEVEL - tilt sensor has either developed an
offset or it is too unlevel as mounted on the
machine.
5.3 TILT SENSOR ELECTRICAL EVALUATION
This basic check using the JLG Analyzer can be used to
test the Tilt Sensor.
• If angle measurements read +20.0, then a sensor/
wiring/connector fault exists. If the readings inter-
mittently display expected angles, then there is likely
a wiring/connector problem and not a failed sensor.
In either case, open the ES Ground box. Disconnect
the sensor, check the wire terminations, and clean
any corrosion on the tilt sensor and control board
connections. Reconnect and test. If the fault persists,
replace the tilt sensor and return the faulty tilt sensor
to JLG with a detailed description of the diagnostic
steps taken.
5.4 ELEVATION ANGLE SENSOR ELECTRICAL
EVALUATION
These basic checks using the JLG Analyzer can be used
to test the Elevation Angle Sensor. If the problem is still
occurring, perform the Tilt vs. Allowed Height Evalua-
tion described below.
• On a level surface, with the Analyzer under DIAG-
NOSTICS/ELEV SENSOR, verify that the elevation
angle sensor voltage increases (ranges from 0.2V-
0.8V to 3.6V-4.2V) with platform height. If not,
check the sensor mounting. If necessary, unbolt sen-
sor and rotate by hand while monitoring with the
Analyzer to check the integrity of the sensor output.
• For machines equipped with an elevation proxim-
ity switch, if the Elevation Sensor appears satis-
factory, verify that the Elevation Prox switch is
opening and closing appropriately by watching
the change of state between the stowed and ele-
vated positions (monitor PROX SWITCH under DIAG-
NOSTICS/ELEV SENSOR). If a change of state is not
observed, check prox mounting and operability by
placing metal in front of the prox sensor face.