There are two methods to resetting the maintenance counter on an HP 4000 Laserjet printer.
The first method is the fastest, but may not work due to many different board revisions.
1. Turn the printer off.
2. Hold down the "Item" key (the minus side of the button) and "Value" key (the minus side).
3. Turn the printer on.
4. Wait for "RESET MAINTENANCE COUNT" to be displayed and then release both keys.
If this method fails, like it did for me, you will have to enter service mode. This mode is generally reserved for service technicians and really the only reason to go into it is to reset the maintenance counter.
To get into service mode:
1 Hold down "Select" and "Cancel Job" while turning on the printer until all of the lights on the Control Panel are lit. Note that if the Control Panel reads INITIALIZING, the keys were released too soon.
2 Press the right side of the "Menu" key, then press "Select". The message SERVICE MODE is displayed.
3. Press "Menus" once to display SERVICE MENU.
4. Once it says SERVICE MENU press ITEM to scroll through service mode items.
5. Once on the Maintenance Counter screen, press "Select" on each number in the Maintenance counter. You can change them by hitting the "Value" key to the left or right and move between the digits by using the "Item" key.
6. To exit the Service Mode press [Go].