Try DIY first — may need a proVerified by FixOffice
Canon E740 — Network (LAN) board error
Applies to: imageRUNNER / imageRUNNER ADVANCE series
What this error means
The Ethernet board failed its check — including missing/invalid MAC address cases. Reseat the network cable and power cycle; a persisting E740 is a NIC board replacement.
Symptoms
- Network printing/scanning dead
- Error after a network change or storm
Try this first (safe DIY steps)
- Reseat the network cable (try a different known-good cable/port)
- Power cycle
- Persisting = NIC board service
Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.
When to call a technician
Board replacement — service.