Boom lift only creeps when raised: elevated drive cutout and tilt
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Applies to: JLG 450A/AJ, Skyjack SJ61T/66T and other boom and scissor lifts
Symptoms
- Drives at full speed stowed, only creeps raised
- Won't drive at all above a certain height
- Tilt alarm while elevated
Why it happens
Lifts limit drive speed when elevated by design. If the stowed or limit switch fails, or the tilt sensor reads off level, the machine stays in slow mode or locks out.
How to fix it
- Fully stow the boom and check that drive speed returns.
- Test the boom stowed and limit switches.
- Check the tilt sensor reading on level ground and calibrate if needed.
- Read the fault code on the controller.
Tools and parts
- Multimeter
- Level
What the factory service manual covers
Controls: limit switch tests, tilt sensor calibration, fault codes. The full procedure, specs and wiring diagrams are in the factory service manual for your machine.