Re: Unlocking fuel door
I double checked the Service Manual and found out 2 things.
1 - Pressure unlocks & Vacuum locks
2 - There are 3 lines, 1 is drivers door, 1 is fuel door, and 1 is for BOTH liftgate and passenger door.
(Assuming no air leak, I think if you accessed the passenger door mechanism, and applied pressure to that air line, you will unlock the rear liftgate, then you are golden!)
If anyone has the passenger door already apart, please test this.
To unlock, the Body Control Module is actuated by the SKREEM. The Body Control Module then sends the signal
to the Central Locking Pump/Security System Module (CLP/SSM) via the Controller Area Network (CAN) Bus. The
CLP/SSM pump motor starts running and supplies air pressure. The door lock actuators are pressurized. When a
pressure threshold is reached in the system, the pump is switched off by an internal pressure switch. The pressure
in the system is then released by the CLP/SSM and the unlocking operation is completed. The locking procedure is
accomplished in a fashion opposite to the unlocking operation. However, the next time the remote control button is
pressed, the CLP/SSM is also actuated by connecting it to ground by the second control lead on the SKREEM. The
direction of rotation for the CLP/SSM pump motor is reversed, thereby providing the vacuum required to lock. In
order to avoid unlocking the vehicle unintentionally, the vehicle is relocked by the CLP/SSM via the SKREEM.
Relocking is accomplished after unlocking with the remote control when: a door is not opened within 40 seconds,
the key is not inserted into the ignition lock, the interior power door lock switch is not actuated, only the liftgate is
opened after unlocking. The CLP/SSM reads the signals (door contacts, trunk lid, interior power door lock switch)
and actuates the power door lock actuators. The vehicle security alarm is also activated by the relocking function.