JLG 18RS Service Manual - Manual (Page 193)

SECTION 6 - JLG CONTROL SYSTEM
3121284 – JLG Lift – 6-51
FUEL ACTUATOR – OPEN CIR-
CUIT 4327 The Ground Module detects an open circuit at the fuel actuator out-
put. (Kubota) The Ground Module controls
revert to Open Loop and restrict
machine speeds to Creep. Check for a good connection at
the solenoid and for continuity
through this circuit. With the
solenoid disconnected, an
open circuit voltage of nearly
8.0V exists on the Ground Mod-
ule output pin for diagnostic
purposes. Inspect wiring for
physical damage. Cycle power
to clear the fault.
FUEL ACTUATOR – SHORT TO
BATTERY 4328 The Ground Module detects a short to battery at the fuel actuator
output. (Kubota) Disable Ground Module Fuel
Actuator output and open the
ground current return path. Inspect wiring for physical
damage and check for wire
continuity. Cycle power to clear
the fault.
FUEL ACTUATOR - CURRENT
FEEDBACK READING TOO LOW 4329 The Ground Module calls for current greater than 250mA, but the
actual current is at least 125mA less than the called for current for
more than 1 second The Ground Module controls
revert to Open Loop control and
restricts all machine speeds to
Creep. Part of the commanded current
is being divided either prior to
the solenoid connection or on
the ground return path. Inspect
wiring for physical damage and
check for wire continuity and a
low resistance return path.
Cycle power to clear the fault.
FUEL ACTUATOR – CURRENT
FEEDBACK READING LOST 4330 Measured feedback current is less than 225mA while Ground Module
output is greater than 40% for a period of 100ms (Displayed on Ana-
lyzer DIAGNOSTICS menu). The Ground Module controls
revert to Open Loop and
restricts all machine speeds to
Creep. Part or all of the commanded
current is being diverted from
the ground return path. Inspect
wiring for physical damage and
check for wire continuity and a
low resistance return path.
Cycle power to clear the fault.
BATTERY VOLTAGE TOO LOW –
SYSTEM SHUTDOWN 441 The Ground Module detects that its supply voltage is less than 9 volts Disable all Ground Module
valve outputs except those
used during Emergency
Descent (Tower Lift Down, Lift
Down, Jib Up/Down). If
MACHINE SETUP
 H&T
LIGHTS = YES or  ENGINE =
KUBOTA D1105 turn off lights
and disable glow plugs.
Perform battery maintenance.
Fault cleared when voltage is
greater than 9.25 volts
BATTERY VOLTAGE TOO HIGH –
SYSTEM SHUTDOWN 442 The Ground Module detects that its supply voltage is greater than
16.0 volts. Disable all Ground Module and
Platform outputs until voltage
is less than 15.75 volts Likely cause is poor alternator
regulation; check alternator.
Cycle power to clear the fault.
LSS BATTERY VOLTAGE TOO
HIGH 443 MACHINE SETUP  LOAD SYSTEM NOT EQUAL
The machine is configured with and Load Sensing System and the
Ground Module detects that the LSS reports supply voltage greater
than 16.0 volts.
Ground Module to set Platform
Load State = Overloaded LSS reports voltage less than
16.0V
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