Lexmark 121.XX error code
Fuser fault
The Lexmark 121 error family indicates a fuser fault: the temperature does not reach or exceeds the operating range, or the sensor signal is invalid. This code stops the printer.
What does this error mean?
The subcode points to the exact cause, such as warm-up, overheating or a sensor. An inadequate power supply through an extension lead, power strip or uninterruptible power supply can also trigger it, so it is worth trying a direct wall connection.
What can you safely try?
- 01Switch the printer off at the main power switch, wait at least 10 minutes for the fuser to cool down, then switch it back on. Many error codes are temporary and disappear after a full power cycle.
- 02Try plugging the printer directly into a wall socket, without an uninterruptible power supply or extension lead.
When should you call a technician?
If the code returns, call a technician: the fuser assembly needs checking or replacement.
Do you rent out or manage printers?
If you manage the printer at a customer’s site, you can record the fault on site in PrinterMS using QR issue reporting, and any parts used are automatically added to its service history. See printer fleet management.
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