asked Jul 11, 2017 at 3:21am
Unknown Printer


While working with HP printer, I am facing the Service Error 79.

Please tell me the solution for this error code.

All suggestions are welcome to this question.

Thanks in advance.

What specific Pro 400 model are you talking about? As in M401? I've seen a few on that model but usually from the PC causing it. The printer tries to auto correct itself by rebooting but as soon as the job queues up on the PC again it kicks the error and the printer reboots getting stuck in that mode or just stops at the 79 error. It's kind of like a 49, firmware error but can indicate hardware failure (usually formatter board).

General advise for any model is try powering the printer on with only the power cord attached, do not have a usb or network cable plugged into it. You can try clearing your print queue as well, hopefully it's not on a wireless network connection or the queue may still try to print so you'll have to clear the queue first and reboot the printer afterwards.

If the machine boots up normally with only power cord attached then it's likely a bad job from a PC/network computer that it didn't like. You can try getting it connected again if the jobs are cleared out and if successful, download/run the firmware update from HP's site, here's the US based link. Updating the drivers as well may help but start with firmware.


The firmware could be corrupt on the formatter and may require a new formatter but most times I've been able to avoid that by clearing the jobs from the PCs and running firmware but remember firmware can only be run on the printer if it is in the ready state with no error codes displayed.

You can look up the service manual for your specific model and find out how to do a cold reset or NVRAM reset before replacing formatter but first eliminate a bad job from PC/network or it may still trigger a 79 even with another formatter installed depending on it's firmware datecode. If able to print a configuration report from internal menu under reports to see what current firmware code is listed, likely HP's site has a newer version available.

by Jay145 on Jul 11, 2017 at 9:02am Add comment