Fault Phenomenon: Skyjack SJ4632 LE electric scissor lift aerial work platform when lifting, the hydraulic pump emits a sharp whining sound.

Troubleshooting Process:
– Checked hydraulic oil level: level too low.
– Checked suction strainer: strainer clogged.
– Checked motor speed: motor reversed (phase sequence error).
– Checked pump body: internal pump wear.

Root Cause: Low hydraulic tank oil level causes pump cavitation and noise.

Required Parts: Add hydraulic oil and check for leaks.