2004 Rear Door Locks by Itself !
 

2004 Limited rear door would not unlatch today. Searched and found solutions to get the door open. First took hatch inner cover off, carefully removed vapor barrier, popped off a plastic cover which exposed the two levers, and got it to open. Lubed everything, reassembled….no success. Still locked when closed and wouldn’t open. Then pulled 10A fuse for ECU-B. Waited 10 sec to reset ECU-B then replaced fuse. Locked everything with fob, then unlocked everything with fob. SUCCESS …rear door was unlocked and could be opened. Closed and opened it several times. Then I noticed it made a locking noise after closing hatch. ARRGH...locked and wouldn’t open! Repeated reset of ECU-B and it would open. But again..seemed to lock itself when closed. Locking/unlocking with fob did not make a difference. Side doors operated correctly….hatch stayed locked.
So is this a programming issue or a faulty ECU-B??? Definitely don’t want to spend a couple hundred dollars if it is not a bad unit.
Any guidance would be appreciated. Thanks!

Important update
 

Well I decided to replace the ECU-B …..which in fact seemed to solve the problem. Now a year later, same problem occurred! Hatch was locking “automatically “ even after pulling fuse and resetting ECU-B. Was getting ready to spring for another unit…..then had a thought. Sitting in the car I followed the owners manual procedures to set, then stop, the security system.

AMAZING…..the hatch would then open/close/open without “automatically” locking. Apparently, the security system somehow had decided to lock the hatch on its own. By setting then stopping it, all is back to operating properly.

Hopefully this will save someone from spending a lot of money on a ECU-B that might not be necessary. Give setting/stopping the security system first!

So the procedure is in the Owner's Manual or is it the Service Manual? Do you have a page number for this?

@mandomaniac

Theft deterrent system section in Owners Manual. Begins on page 33. On page 34 I noted “ if the alarm has been activated and the key is not in the ignition switch, all the side doors and back door will relook automatically “
That seemed to be what was happening…..even when the vehicle was completely unlocked by double clicking the fob, I could hear the hatch lock a few seconds after it finished closing.
I suspect the system had been activated by the battery discharging while we were away….then being charged.