PROBLEM 6
The crawler travels only at a slow speed.
POSSIBLE CAUSES
Partial control voltage from the handle to the PC, partial control voltage from PC to pump EDC, worn pump or motor.
CHECKS
Check the travel speed switch for high-speed selection. Check for 100% travel speed on the travel Diagnostic screen.
Selected
Not Selected
Is the two-speed travel valve receiving a voltage signal from the controller?
Select high speed with the switch.
No Yes
Check the two-speed travel valve for mechanical
problems by manually enabling the spool.
Is engine RPM more than 1,500 on the Information screen?
Problem
Yes No
No Problem
Repair or
replace the
valve.
Check RPM sender for
the correct operation.
Remove the plug at the motor port M5 and
check orifice for obstruction.
(See Section 2 - Pump Components.)
Increase the
engine speed.
Obstruction No Obstruction
Is the throttle in maximum RPM position?
Yes No
When moving the travel handles fully in both directions, does the travel
Diagnostic screen show 100% pump control in each direction?
Yes No
Are 28 volts present (full speed) at both sides of the EDC coil?
Check the coil for a resistance of 17 to 19 ohms at pump.
(See Section 3 - Checking Electrical Inputs/Outputs.)
Consult your Manitowoc dealer or
the Crane Care Lattice Team.
Voltage and Coil Ok
Voltage and/or Coil not Ok
Is the system pressure above 269 bar
(3,902 psi) at motor port M4? (See Section
2 - Motor Components.)
No
Repair or replace the coil or wiring.
Check for pump or motor leakage. (See Section 2 -
Motor Leakage Test.)
Clean or replace the orifice.
When moving the travel handles fully in both directions, does the travel Diagnostic
screen show the handles at 100% in reverse or in the forward direction?
Yes No
Replace the control handle, node-2
controller, or repair the wiring.
Yes
Slow speed is at
required speed.
Brake partially applied. Check the brake
pressure source.
No
Yes
Check the brake and accessory/MAX-ER pump output.
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