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critical HP

Error Code Service light

Blinks to indicate a serious device malfunction that needs professional attention from service personnel.

? What Causes This

Issues related to severe hardware failure inside the printer, often not resolvable without specialized tools or expertise.

How to Fix It

Contact technical support immediately for further instructions on how to proceed.

Source: page 17 of the official manual

From the manual

Manual page 17 — HP error Service light

This error code appears in:

HP Laserjet Pro 3001 3008dn DW Printer