JLG 15/20MSP Service Manual - Manual (Page 137)

SECTION 6 - TROUBLESHOOTING
3121231 – JLG Lift – 6-17
6.11 FAULT CODE TROUBLESHOOTING TABLES
Machine in Drive Speed Cut-Back (Turtle) Mode All The Time
Overview of Procedure
Under normal machine operation once the platform is elevated the machine’s maximum drive speed is reduced to 1/4 the
normal drive speed of when the platform is fully lowered. This is detected with a drive speed cut-back (proximity) switch
mounted at the base of the mast assembly and a target mounted on the mast assembly. When the mast is elevated and the
target raised the proximity switch then cuts back the machine drive speed. When machine is in the drive speed cut-back
mode a turtle is displayed on the Ground Control Module LCD display.
Check For These Obvious Conditions First:
• Mast drive speed cut-back (proximity) switch and target plate secure and undamaged.
• Both Pot Hole Protection Bar Limit switches secure and undamaged.
Table 6-5. Machine In Drive Speed Cut-Back (Turtle) Mode All The Time
STEP ACTION SPEC YES NO
1. The Pot-Hole-Protection system bars should be raised when the platform is
fully lowered. Check if the Pot-Hole-Protection bars are down when the plat-
form is fully lowered. — Check the
mechanical
operation of
the PHP System
Go to Step 2
2. With the platform fully lowered, check for continuity on the Cutback Proxim-
ity Switch wires between pins-8 and 18 on the P2 connector at the Ground
Control Module. — Go to Step 3 Repair or Replace
Speed Cutback
(Proximity) Switch
3. With the platform fully lowered, bars raised, check for continuity on the
Right Side PHP bar limit switch, between pins-9 and 19 on the P2 connector
at the Ground Control Module. — Repair or Replace Right Side
PHP Limit Switch
Go to Step 4
4. With the platform fully lowered, bars raised, check for continuity on the Left
Side PHP bar limit switch, between pins-10 and 20 on the P2 connector at
the Ground Control Module. — Repair or Replace Left Side
PHP Limit Switch