Page 111
65-J Desel - Servce & Parts Manual
February 2021
Secton 19 - Troubleshootng
7-7 Flash code on
GP400
Indicates an attempt to start was
sent by the GP400 but the oil
pressure switch did not close.
Check all the above
Starter cranks but
engine will not start
Low fuel reservoir
Check/fill fuel reservoir. Fuel system requires air purge after loss of
fuel.
Air trapped in the fuel system
Purge air from the fuel system (See Section 18 - Mechanical
Components for instructions). Check fuel reservoir level or for leaks in
the fuel hoses.
Restriction in the fuel system
Replace Fuel Filter. Check fuel supply hoses
Malfunctioning fuel solenoid
Check/replace fuel solenoid located on the top of the injection pump.
Malfunctioning glow plugs (cold
climates)
Test/ replace grid heater relay, fuse and grid heater
Obstructed air filter
Clean/replace air filter.
Contaminated fuel
Test/replace fuel
Other engine issues
See engine manufacturers troubleshooting guide
No high throttle
Malfunctioning throttle controller,
solenoid or blown fuse
Test/replace throttle controller and/or throttle solenoid and fuse
Restriction in the fuel system
Replace Fuel Filter. Check fuel supply hoses
Obstructed air filter
Clean/replace air filter.
Other engine issues
See engine manufacturers troubleshooting guide
Problem
Possible Cause
Remedy/Solution
Boom Lift/Lower
Platform will not raise
Excessive weight on platform
Reduce weight to within platform capacity
Machine out of level (platform
elevated above 10’)
Indicator light will be illuminated and alarm will sound off.
Reposition machine to level ground.
Main relief valve (6) out of
adjustment
Adjust Main relief valve (6) to rated platform capacity located on
function manifold - see hydraulic section.
Lift valve (8.1) not energized
Check wiring to lift valve. Check for EZ-Cal message or flash code
Lift valve (8.1) not shifting
Clean debris. Check for damage/replace.
Solenoid Valve (18) dump valve
not energized
Check wiring to valve. Check EZ-Cal ref. P4-14 for output.
Solenoid Valve (18) load sense
dump not shifting
Clean debris. Check for damage/replace.
Main system pressure inadequate
Check pump output flow and pressure
Lift/Lower joystick inoperative
Check Joystick output using EZ-Cal ref. 2D-2
P7-1 for analog joystick output signal
Battery discharged - no charge
output
Check battery voltage, alternator output (14.5 volts) Check GP400 for
4-4 flash code.
System interlock
Check EZ-Cal HELP messages for interlock
Platform will not lower or
lowers slowly
Lowering valve SV3 not
energized
Check wiring to lowering valve located inside control module - Section
25 - Hydraulics for location.
Lowering valve (8.2) not shifting
Clean debris. Check for damage/replace.
System interlock
Check EZ-Cal HELP messages for interlock
Main system pressure inadequate
Check pump output flow and pressure
Emergency lowering not
working
Battery discharged, not charging
Check/charge battery. Check charge Isolator relay and fuse.
Check alternator output (14.5 volts)
Auxiliary power unit malfunction
Check APU located beside lower control box
Emergency Down switch failure
Check/replace switch.
Lowering valve (8.2) not shifting
See “Platform will not lower or lowers slowly”
Counterbalance Valve (on lift
cylinder) not adjusted correctly
Contact Factory Technical Support for instructions for counterbalance
valve adjustment
System interlock
Check EZ-Cal HELP messages for interlock