2003 honda pilot, the dvd player plays the sound but shows "error 877" on the screen.

SOURCE: DVD player isn't showing anything

do you hear movement inside like disc rotating, if so then the switch that closest lid is damaged. This is when you fold dvd down it hits this switch to turn monitor off. It could be damaged. If there is no noise or movement then power supply has damaged or batt dead and no power goes to it from power cord.

SOURCE: black rectangle at bottom of screen when playing dvds on sony dvd player

Had the same problem but was able to fix it by simply doing the following:
"this is closed captions turned on your TV. get your original TV remote and look for a button that says "Captions" or "CC", and keep pressing it until the TV says "Off". if it doen't have one of those buttons, you will need to get into the menu of the TV and turn off closed captions there. It is probably set on "Text1 or Text 2" right now, and it needs to be set on "Off"

SOURCE: CD player wont play disks, showing error 1 instead

The original user manual will define the headunits error readings. It is most likely an internal mechanical failure and will need to be repaired or replaced

SOURCE: DVD player will not play

well if this is a factory system you dvd unit is bad and if its not you should replace unit sound like your dvd reader in the unit is not working

SOURCE: Knock Sensor installation for 2003 Honda Pilot

I don't know where the knock sensor is exactly on this engine, but if you buy the replacement first it will help you identify it.

It's screwed into the block near the head or the head itself. It has an electrical connector attached to it (two wires, I believe).

The replacement is pretty simple: remove the electrical connector from the old one; screw it out with a wrench; screw the new one in and; plug the connector onto it.

Charlie