32DFR114.A
4 - 2
TABLE 4-1: TROUBLESHOOTING GUIDE
Function
Symptom
Possible Cause
Remedy
Flow control valves are
closed
Adjust valves as shown in section C.5 in this
chapter.
Flow control valves are
clogged
Clean the valves. Adjust valves as shown in
section C.5 in this chapter.
Air in hydraulic system
Cycle ramp to bleed system. Refill hydraulic fluid
reservoir as required.
Loose or faulty wiring
at hydraulic pump
Check for DEPLOY VALVE INPUT signal at
connector J8 (black lead). Repair harness, as
required.
Pump motor defective
Replace hydraulic pump assy.
Directional valve
defective
Replace hydraulic pump assy.
Hydraulic rotary
actuator defective
Replace hydraulic actuator.
Pump solenoid
operates, but no ramp
movement occurs
Electronic controller
defective.
Check for DEPLOY VALVE INPUT signal at
controller connector J4, pin 1. Replace
controller, if necessary.
Sensor target requires
adjustment
Adjust sensor target; refer to section B.6 in this
chapter.
Needle valve setting is
too restrictive
Close both needle valves by turning them fully
clockwise. Readjust valves as shown in section
C.5 in this chapter.
Hydraulic fluid level
low
Check hydraulic fluid level; refill as required.
Low hydraulic
pressure
§
Check that hydraulic pump pressure output is
1400 PSI. Adjust pump relief valve as
necessary.
§
Check pump and hydraulic lines for leaks or
obstructions; repair, as required.
§
Replace hydraulic pump assy.
Hydraulic rotary
actuator defective
(binding or jammed)
Repair or replace hydraulic rotary actuator.
Ramp hinge or ramp
drive arms defective
(binding or jammed)
Repair or replace defective parts.
Ramp deploys very
slowly or stalls when
DEPLOY switch is
pressed
Wiring harness leading
to pump is defective
Check wiring harness leading to pump. Repair
wiring, as required.
Ramp deploys
normally but stalls at
halfway point
Deploy sensor or
sensor target is out of
adjustment.
Adjust target as shown in section B.6 of this
chapter.
Hydraulic pump
solenoid defective
Replace solenoid.
Hydraulic pump relay
defective
Replace relay.
DEPLOY
function
inoperative
or erratic
(cont.)
Hydraulic pump does
not shut off when
ramp is fully deployed
Electronic controller
defective
Check for 0 VDC at controller connector pin J4-4.
Replace controller, if necessary.
