Update message always.

10 Tips for Troubleshooting Your Printer
http://www.pcmag.com/article2/0%2c2817%2c2412253%2c00.asp

My Printer Won't Print
If the printer doesn't respond when you try to print a document, make sure it's turned on and that a cable hasn't come loose. For both USB- and network-connected computers, the printer driver must be installed on the computer you're printing from. Occasionally the driver may become corrupted and have to be re-installed.
You can either do this from the disc supplied with the printer or by downloading the driver from the manufacturer's Web site. Printer makers generally have a page for which you can download available software for different models and operating systems. (You may also have to update the driver so that it's compatible with a new operating system, as many consumers buying Windows 8 computers have discovered.
Not sure if your computer already has a driver installed for the printer you want to use? With Windows, it's easy to check. Just open the printer folder from the Start menu or Control Panel. Depending on the version of Windows, it's either called Printers, or Printers and Devices. It will show a list of available printers, with offline printers grayed out. If your desired printer is offline, make sure it's properly connected to your PC or network. The default printer has a green check next to it. You can set another printer as default by right-clicking on it and following the prompts.
Right-clicking on a printer and clicking on Printing Preferences will reveal the driver settings. By tweaking them, you can adjust a number of functions, including but not limited to paper size and type, default paper tray, print quality, and duplex printing (if available). The printer software installation disc almost always includes a convenient interface to access printing functions, but it's faster to work straight from the driver.
Most new printers include a quick-start sheet, and many include a user manual. You should keep the installation disk and user manual in a convenient place. A growing number of printers include a user manual as a PDF file on the installation disk, or make it available from their Web site. It's always a good idea to download it to your PC.
HAVE A NICE DAY.

Please download the firmware update from the Lexmark website www.lexmark .com and install the patch http://bit.ly/pWGkeE after updating.

Most commonly, LaserJet printers are accessed over a network. To workaround the issue, you may try to connect your PC directly to the printer using an IEEE-1284 compliant cable.
or update your driver
The PCL XL error may occur if one or more of the required driver files are missing from your computer or are outdated. In this case, you may visit the HP Website for the latest driver updates, download them, and update the existing driver files.
If the problems with the PCL 6 driver continue to occur, remove it from your system. After removing, install the PCL5 printer driver that is shipped with your HP LaserJet Family Printer. If this driver is not available, use the latest preinstalled driver that is available on your Windows computer.

hope this helps

Sounds like you cover all the bases. I just wonder if you reset the unit via the service mode?
resetting the printer should have cleared the memory.

Hold down select and return while powering on machine, hold until self test comes up on display then press go, this will get you into service mode.

Run the memory diagnostics.

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_8b8c2cd6ce148309

first of all, download updated driver from software.canon-europe.com and install ( before install, remove old drivers and programs)
and if appears again, change your network cable.

Do you have the update and networking on? Sometimes the networking will turn off and messages won't send. Or if you're in the middle of a mall or shopping center they won't send either.

Usually these messages are from communication issues between the computer and the printer. I have to go to the printers support/driver site and download the latest and greatest drivers for that printer that matches the operating system. I then uninstall the printer and get rid of all software and drivers for it. Make sure the printer is unplugged and off. Install the new drivers. If this printer is connected to a router and all computers in the home access it through the network, then it can be reinstalled simply by powering it up, attaching it to the router with an ethernet cable, opening up the control pane > click on printers > click on add printer > choose network printer > windows will search the network and find the printer and display it. Highlight the printer when it displays and click ok. Windows will install and initiate the printer and ask you if it is to be the default printer and will ask if you want it to print a test page.

If this printer is connected to the computer via usb cable, once the drivers are installed, attach the cable to the printer and start it up, windows will recognize the hardware and automatically load the drivers you installed. It may want to search windows update for an updated driver, click ok and let windows set the printer up....that includes all communication protocols.

Hi Savo,

Is printer being recognized by network? What does device manager indicate? If there is a Yellow exclamation point, you need an updated driver. Try uninstalling software, removing access cable to printer and reinstalling software then re-connecting printer cable.

I don't have an answer, but I can add some detail since I have the same problem (6250 that suddenly won't duplex).

I have a wired network with multiple Vista machines connected and have been duplexing just fine for YEARS with the same PCs and same drivers. One day my wife complained she couldn't duplex and I messed around, updated drivers, rebooted everything, etc. etc. and finally gave up and sent the print job from my laptop where it duplexed just fine.

About a week or so later I noticed that my laptop would no longer duplex either! Once again I updated the drivers, rebooted, tried different settings, etc. etc. but no luck.

I'm pretty convinced that a Windows patch has caused this issue (which is why there is a timing difference between my machines). I've rolled back my system to remove several patches and things seem to work fine again, however I'm not exactly sure which patch causes the problem AND within a few days Microsoft reinstalls the patch automatically.

Unfortunately I'm not confident that Xerox will put much effort into fixing this driver problem since this is not only an "old" printer, but I don't think many people do much duplexing (so there won't be many people yelling for help).

I'll let you know if I find a better work-around or fix.

try new drivers from www.brother.com