Twr Length Sensor Not Detecting Length Change - JLG 1250AJP Troubleshooting Manual

SECTION 1 - FAULT DICTIONARY AND SELECTED TROUBLESHOOTING

1.365 TWR LENGTH SENSOR NOT DETECTING LENGTH CHANGE

Flash Code: 8-4
Tower length sensor not detecting length change. The control system did not detect at least 0.3"of movement within 3 sec-
onds while the tower telescope function was commanded. This fault is not detected for tower telescope within 5" of the max-
imum or minimum mechanical length.
Note Pretest Instructions
1.365.1 Check fault log
1.365.2
1.365.3
1.365.4 Connect a 1000 psi pres-
sure gauge to MP1 on the
main valve manifold
1.365.5 Connect a 5000 psi pres-
sure gauge to MP1 on the
main valve manifold.
Remove the solenoid from
the main tele proportional
valve.
1.365.6 Disconnect main dump
valve solenoid [X074]
1.365.7 Swap the main dump enable
valve [X074] cartridge with
the main lift enable valve
[X082] cartridge. Connect a
5000 psi pressure gauge to
MP1 on the main valve man-
ifold. Remove the solenoid
from the main tele propor-
tional valve, but keep sole-
noid connected to the
harness.
1.365.8 Disconnect PVG enable
valve connector [X068]
1.365.9 Swap the PVG enable valve
[X068] cartridge with the
main lift enable valve [X082]
cartridge.
1-166
Test
Are there any other tower length sensor or
tower tele PVG or tower tele enable faults?
Examine the electrical connections at the
tower boom length sensor [X093] and BLAM
module J3 connector [X088]. Are there any
loose connections, moisture or corrosion?
Are the tower boom length sensors #1 (Top)
[X093] and #2 (bottom) [X094] properly
mounted to the machine. -AND- Are the sen-
sor cables free to move with boom?
With the machine idling, does the gauge read
400 - 450 psi?
While activating main telescope in, does the
gauge read 3400 psi?
Does the solenoid measure 7.2 Ω?
While activating main telescope in, does the
gauge read 3400 psi?
Does the solenoid measure 7.2 Ω?
Does fault clear?
1250AJP
Result Corrective Action
Yes Troubleshoot them first
No Go to step 1.365.2
Yes Clean or replace any bad connections
No Go to step 1.365.3
Yes Go to step 1.365.4
No Remount/repair any affected sensor
Yes Go to step 1.365.5
No Adjust the low pressure relief on the function
pump till gauge reads 450 psi. See Figure 3-2.
Pumps Layout on Pg. 248 for location. If adjust-
ment does not correct the pressure, replace the
control valve on the function pump.
Yes Go to step 1.365.8
No Adjust the high pressure relief on the function
pump till the gauge reads 3400 psi while activat-
ing the function. See Figure 3-2. Pumps Layout
on Pg. 248 for location. If adjustment does not
correct the pressure, go to step 1.365.6.
Yes Go to step 1.365.7
No Replace solenoid
Yes Replace the cartridge originally from the main
dump valve
No Replace the control valve on the function pump
Yes Go to 1.365.9
No Replace PVG enable valve solenoid [X081]
Yes Replace cartridge originally in PVG enable valve
[X081]
No Go to step 1.365.10
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