My Pioneer DEH-P9800 BT faceplate won't close

Clean all contacts chemically and check all wiring for good, tight connections.

Sometimes the mechanism is misplaced, just disassemble that mechanism and turn on radio without the secondary plate and wait until the motor to get to the final position when it turns off again, reassemble.

look for any guide holes sometimes their are two per side and an access tool is needed to depress them

The face folds down to give you the option to remove the face if you want. It will return to the upright position a few seconds later whether you remove the face or not. There should be a tab on the underside of the face you can push should you decide to detach the face from the chassis.

The faceplate and head unit is is attached via a flat ribbon cable. (Caution only continue if you have some courage). If you open the faceplate you will see that the ribbon cable is seated in too a flat connector on the PCB (Printed Circuit Board). This connector has a locking mechanism on it that when locked presses the contacts of the cable to the connector. Ensure that the cable is seated properly and that the latch or the lock is in the locked position. Assuming that the tension lessons when the unit is closed so it draws away from the connector and when the unit is open it pulls tension creating a contact. If you see no signs of mishap on this end of the connector try the other end.
Hope this helps.

remove the unit and disconnect the battery+red and yellow cables.check the front unit for derfomed plastics or stucked somehow microswitches!someone stucked from the heat!

Problem solved by downloading manual for next model up which includes all the features of the lower one. DEH-P9800

Hey sparrow, sorry you didn't get an answer to this sooner, mine just started doing the same thing. After fidling and dismantling for an hour or so I think I have diagnosed it to being the ribbon cable which comes from the circuit board to the front most control panel is cracked (i.e. the cable that connects to the connectors on the removable face plate) When the panel attempts to open fully the ribbon cable is flexed enough to lose connections making the unit think the faceplate has been removed and so attempts to close...when it closes the connectors retouch causing it to think it needs to reopen....this is a nasty design flaw for a unit that cost me $1500 (admitedly 10 years ago but it was in a box in the cupboard for 8 of those years) !!!! Now any chance I can source this $2 part .....eek

I have a similar problem, but only when the AUX1 input (bottom of the faceplate) has something connected.
I am looking to solve this problem.

Its the ribbon cable needs replacing going from the deck to the faceplate