Tray Error - Invalid Config

Possibly the the eject switch is stuck, open the case carefuly check and rectify.

Make sure the paper try is properly attached. Try to unplug the power of your pinter and the USB cable for about 2-3 minutes. Restart your computer. Plug the USB and power to the printer then turn it back on.

Device error An internal error occurred in the device. Press (Select) to resume the job. - Door open The printer door is open. The door must be closed before printing can continue. - Engine comm. error The device experienced an internal communication error. This is a warning message only. Job output might be affected. - Invalid driver You are using the incorrect printer driver. Reselect the printer driver appropriate for your device. - Invalid entry Invalid data or response. Correct the entry. - Jam in Cartridge area A paper jam has occurred in the print path. Open the door and clear the jam. Then press the (Select) button on the control panel - Jam in Output bin A paper jam has occurred in the output area. Clear the jam, and then press the (Select) button on the control panel. - Jam in print paper path. A paper jam has occurred in the print path. Open the door and clear the jam. Then press the (Select) button on the control panel. - Jam in tray 2 A paper jam has occurred in Tray 2. Clear the jam, and then press the (Select) button on the control panel. - Jam in tray 3 A paper jam has occurred in Tray 3. Clear the jam, and then press the (Select) button on the control panel - Load paper The HP Color LaserJet 1600 printer is out of paper. Please load specified paper type into the tray indicated. - Load Tray X [TYPE] [SIZE] The printer is processing job, but the tray indicated is empty. Please load specified paper type and size into the tray indicated. - Manual feed The printer is waiting for paper in the tray indicated Load the paper as indicated. - Memory is low The device memory has been almost completely filled. Allow the device to finish the job, or press (Select) to cancel the job. Break the job into smaller jobs that contain fewer pages. - Misprint The printed pages have been incorrectly placed on the paper. To continue, press the (Select) button on the control panel.

Printers & Copiers
Code error E03

try this. It is the reset for the waste ink error (8 flashes)

1) With the printer power OFF, while pressing the Resume button, press the Power button. (Do not release the
power button.)
2) While pressing the Power button, release the Resume button, press the Resume button again twice, and then
release the Resume button and Power button.
3) The green indicator flashes during initialization.
When the indicator stops flashing and remains on, press the Resume button 4 times to clear waste ink message.
(The indicator toggles between orange and green each time the Resume button is pressed.)
4) Next, press the Power button, and the green indicator will light, and the function will be executed.
5) Turn off the printer then back on and error should clear.

a 49.xxxx error on an HP means that there is an issue with one or more hard disks. you can try to re-initialise the hard disk(s) by rebooting the printer while holding the green button. when the three leds are lit, release the green button, and navigate using the numerical buttons until you see "initialise hard disks" on the display of the printer. confirm by pressing the green button again. if all goes well, your printer will take two minutes longer than usual to boot. if you still get the same error afterwards, you need to replace the disk.

unplug, and replug the power cord, then try to power on, after that try to open the carriage and check for any obstructions that maybe locking or obstructing the path of the printer head from moving left to right.

Message:
TRAY ERROR INVALID CONFIG

What this message means:
The printer detects an incorrect configuration of the trays.

What you can do:
Turn off the printer. Set the trays in the proper configuration again.
See "Installing the Optional Tray Module" in the manual book.

Please find below a link to give you a brief idea on the process. Exact details can be viwewed from the manual only:
http://www.csudh.edu/CLASS/voffice/dell3100printer/Contents/section08.html#513263

1) take a flash light and inspect the paper path just to make sure there really is nothing there.

2) print a test page from the printer by pressing the big button ( I think) one of the buttons, can't remember I work on so many models

3) take out cart. turn off then on, install cart. and do step 2

what happens

You can restore the original factory default menu settings by initializing NVRAM. Try this and see what happens. from there I would need an exact message off the printer to help further.
Turn off the printer.
Turn on the printer while holding down and .
The Customer Mode menu appears.
Press Menu.
Press until Configure appears, and then press or .
Press until Maintenance appears, and then press or .Press until Init NVRAM appears, and then press or .
The Init NVRAM Are you sure? message appears on the operator panel. Press .
Turn off the printer, and then on again.