JLG 2658E3 Service Manual - Manual (Page 53)

SECTION 3 - TROUBLESHOOTING
3120878 – JLG Lift – 3-1
SECTION 3. TROUBLESHOOTING
3.1 GENERAL
This section contains troubleshooting information to be
used for locating and correcting most of the operating
problems which may develop in the aerial platform. If a
problem should develop which is not presented in this
section or which is not corrected by listed corrective
actions, technically qualified guidance should be obtained
before proceeding with any maintenance.
3.2 TROUBLESHOOTING INFORMATION
The troubleshooting procedures applicable to the aerial
platform are listed and defined in Table 3-1, Hydraulic Sys-
tem Troubleshooting.
Each malfunction within an individual group or system is
followed by a listing of probable causes which will enable
determination of the applicable remedial action. The prob-
able causes and the remedial action should, where possi-
ble, be checked in the order listed in the tables.
It should be noted that there is no substitute for a thor-
ough knowledge of the equipment and related systems.
It should be recognized that the majority of the problems
arising in the machine will be centered in the hydraulic
and electrical systems. For this reason, every effort has
been made to ensure that all likely problems in these
areas are given the fullest possible treatment. In the
remaining machine groups, only those problems which
are symptomatic of greater problems which have more
than one probable cause and remedy are included. This
means that problems for which the probable cause and
remedy may be immediately obvious are not listed in this
section.
The first rule for troubleshooting any circuit that is hydrau-
lically operated and electrically controlled is to determine
if the circuit is lacking hydraulic oil and electrical control
power. This can be ascertained by overriding the bypass
valve (mechanically or electrically) so that oil is available
to the function valve, then overriding the function valve
mechanically. If the function performs satisfactorily, the
problem exists with the control circuit.
3.3 HYDRAULIC CIRCUIT CHECKS
The first reference for improper function of a hydraulic sys-
tem, where the cause is not immediately apparent, should
be the Troubleshooting Chart. The best place to begin the
problem analysis is at the power source (pump). Once it is
determined that the pump is serviceable, then a system-
atic check of the circuit components, beginning with the
control, would follow. For aid in troubleshooting, refer to
the Illustrated Parts Manual for hydraulic diagrams of the
various circuits.
3.4 JLG SMART SYSTEM™
The JLG SMART System™ uses a 24 Volt multiplex motor
control unit, working in conjunction with a joystick control-
ler and several switches, to operate all machine functions.
The SMART System™ has a built-in LED to indicate any
faults which occur during operation of the machine. The
system also stores the last ten trouble faults for use in
troubleshooting the machine. Each fault is indicated by a
first sequence of flashes, then short pause, followed by a
second sequence, then a long pause before everything
repeats.
When a fault occurs in normal operation, the flash fault
repeats while the fault is present; as far as possible nor-
mal operation continues. If there is more than one fault
present, the ‘most important two’ will be indicated alter-
nately. Faults are grouped according to the first digit; the
second digit provides an extra diagnostic indication.
In addition, the control unit may be programmed for any
future options that are added to the machine. The SMART
System™ may be adjusted using a custom designed ana-
lyzer or special system software installed on a personal
computer (PC) or a laptop computer, operating under
DOS or Windows. Both the analyzer (JLG kit no. 2901443)
and the computer software (JLG kit no. 2900874) are
available from JLG and include a connecting cable and
SMART System™ adjustment procedures.
WHEN INSTALLING A NEW SMART SYSTEM CONTROLLER ON
THE MACHINE, IT WILL BE NECESSARY TO PROGRAM THE CON-
TROLLER FOR THE PROPER MACHINE CONFIGURATION,
INCLUDING OPTIONS. REFER TO ANALYZER KIT NO. 2901443.