JLG 18RS Service Manual - Manual (Page 191)

SECTION 6 - JLG CONTROL SYSTEM
3121284 – JLG Lift – 6-49
JIB LIFT DOWN VALVE – SHORT
TO BATTERY 3419 The Platform Module detects a short to battery at the Jib Lift Down
Valve output and reports it to the Ground Module. Jib Lift Up and Down outputs
are disabled. Check for a good connection at
the solenoid and for continuity
through this circuit. Inspect
wiring for physical damage.
Cycle power to clear the fault.
JIB LIFT DOWN VALVE – SHORT
TO GROUND 3420 The Platform Module detects a short to ground at this output and
reports it to the Ground Module. Jib Lift Up and Down outputs
are disabled. Inspect wiring for physical
damage and check for wire
continuity. Check for coil dam-
age or shorting condition in
connector. Cycle power to clear
the fault.
FUEL SENSOR SHORT TO BAT-
TERY 431 Ground Module fuel sensor input (J2-25) detects a voltage higher
than 2.50 volts The Control System shuts down
all fuel level indicators in Plat-
form and Ground stations. Disconnect fuel sender and ver-
ify resistance readings can
range from approximately
30ohms (full) to 240ohms
(empty). If not, replace sender.
With fuel sender connected,
backprobe J2-25 and verify
voltage range from approxi-
mately 0.5V to 2.3V. Trouble-
shoot wiring or connections.
FUEL SENSOR SHORT TO
GROUND 432 Ground Module fuel sensor input (J2-25) detects a voltage less than
or equal to 0.3 volts The Control System shuts down
all fuel level indicators in Plat-
form and Ground stations. Disconnect fuel sender and ver-
ify resistance readings can
range from approximately
30ohms (full) to 240ohms
(empty). If not okay, replace
sender. With fuel sender con-
nected, backprobe J2-25 and
verify voltage range from
approximately 0.5V to 2.3V.
Troubleshoot wiring or connec-
tions.
OIL PRESSURE SHORT TO BAT-
TERY 433 MACHINE SETUP  ENGINE = KUBOTA D1105
Oil Pressure reads a high value at Startup even though the engine has
not been started (occurs for STB or OC – wire off pressure switch)
If MACHINE SETUP  ENGINE
SHUTDOWN = ENABLED then
engine start is not permitted;
Low Oil Pressure indicator will
be activated
Verify wire is connected to oil
pressure switch. With engine
off, switch should show low
impedance to ground or
replace switch. Observe state
change on Analyzer under
DIAGNOSTICS-->ENGINE--
>ENGINE OIL PRESS
COOLANT TEMPERATURE
SHORT TO GROUND 435 MACHINE SETUP  ENGINE = KUBOTA D1105
Ground Module coolant temperature input (J1-14) detects a voltage
less than or equal to 0.05 volts
If MACHINE SETUP  ENGINE
SHUTDOWN = ENABLED then
engine will be shutdown
High Engine Temperature indi-
cator will be activated
Disconnect temperature
sender and verify resistance
reading > 0.15ohms (up to
50kohms is acceptable); then
troubleshoot wiring. With sys-
tem on, backprobe J1-14 and
verify voltage > 1.5V.
Table 6-5. Fault Code Troubleshooting Information
Help Message DTC Condition Producing DTC
Control System Response or
Machine Condition
Corrective Action/
Operational Requirement
for Function Movement
and/or to Clear Fault