Sharp H3-xx / H4-xx — Fusing temperature fault family

What this error means

High-temperature (H3) and low/abnormal-temperature (H4) faults in the fusing unit. Standard fuser-class fault: lockout, likely latching.

Symptoms

• Stops at warm-up or mid-job

Try this first (safe DIY steps)

1. One power cycle only; no repeated resets on temperature faults

Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.

When to call a technician

On recurrence.