!!
critical HP
Error Code LED blinks 5 times, red light on
Severe hardware or software error, service is required.
? What Causes This
Unknown hardware failure or corrupted firmware.
✓ How to Fix It
Contact service technician for repair.
Source: page 4 of the official manual
From the manual
This error code appears in:
HP Laserjet Mfp M139 M142 Printer