The power door lock subsystem is made up of the following components:

The remote function actuator (RFA) module is the door lock master device. This means the RFA has final control over whether or not doors will lock or unlock. The RFA will not allow any doors to be locked with the power lock system unless the key is out of the ignition and the doors are all closed. The passenger door jamb switches status is reported by the passenger door module or the rear door module to the driver door module over the SBI. The DDM then reports the passenger door switch status as well as the driver door switch status to the RFA via the Class 2 serial data system.

The driver's door module (DDM) directly controls the driver's door lock actuator motor, the driver window and the driver outside rear view mirror.

The DDM receives the passenger door lock and the driver door lock messages via the SBI system and forwards driver's door switch lock request messages to the remote function actuator (RFA) via the Class 2 serial data link. The RFA receives the request message and checks for lockout prevention criteria. If the conditions are proper, the RFA sends a lock or unlock command message back to the DDM via the Class 2 serial data circuits. The DDM forwards door lock messages received from the remote function actuator (RFA) to the passenger door module (PDM) and the rear door module (RDM) over the simple bus interface (SBI).

Battery voltage is always applied to the DDM through a dedicated DDM fuse in the IP fuse block.

The passenger's door module (PDM) controls the passenger's door lock actuator. The PDM monitors the passenger's power door lock switch. The RH front door power window and outside power mirror are also controlled through the PDM.

Battery voltage is always applied to the PDM through a dedicated PDM fuse in the IP fuse block.

The rear door module (RDM) controls both rear door lock actuators. The RFA commands the DDM to lock or unlock the doors via a class 2 serial data message. The DDM then forwards this command to the RDM in the form of a simple bus interface (SBI) serial data message.

Battery voltage is always applied to the RDM through a dedicated RDM fuse in the rear fuse block.

The LH power door lock switch feeds the LH front power window switch which then transmits a switch activity message to the DDM. The driver door window switch is a multiplexed switch device that communicates with the driver's door module (DDM) via the simple bus interface (SBI) serial data link.

The RH front power door lock switch directly switches the passenger door module (PDM) input. The PDM then transmits a switch activity message to the DDM over the simple bus interface (SBI).

The power door lock actuators receive their power from the door modules. The door modules apply battery voltage of the correct polarity to their respective door lock motors when any door lock or unlock command is received, driving the door lock lever in or out. The power door lock switches are generally closed for just a moment. If the power door locks are commanded for too long, an circuit breaker in each actuator will open to protect the motor against damage. The circuit breakers have positive temperature coefficients (PTC) and will reset automatically when voltage is removed from the actuator. When either the left or right front power door lock switch is activated, all of the doors are locked or unlocked in unison. When the driver's door key cylinder is turned, all doors will unlock via the power lock system. The key locks and manual lock levers will still work if electrical power is lost.

Each door lock actuator assembly contains a manual door lock lever. The rear doors have no power lock buttons, only manual lock levers. The lock levers move with actuator position and may be used to independently lock or unlock any individual door at any time. Both front doors have key cylinders that will unlock and lock the doors by manually moving the front door lock actuators

The class 2 and simple bus interface (SBI) are both serial data links. The serial data links replace cables in the vehicle by multiplexing (time-sharing) data to and from each device over a single wire referenced to ground. If the SBI is lost, both the rear door module (RDM) and the passenger door module (PDM) enters the sleep mode. With the RDM and the PDM in sleep mode, no power door lock operations are possible.

When the passenger power door lock switch is pressed, the following events occur:

1. The passenger door module (PDM) will directly sense actuation of the passenger door power lock switch.
2. The PDM will send a serial data link message via SBI to the driver's door module (DDM) requesting that the doors be locked.

The driver door module will receive a SBI message from the driver door window switch assembly when the driver door lock button is pressed.

3. The DDM receives and forwards the lock request message to the remote function actuator (RFA) via the class 2 serial data link.
4. The RFA receives the request message and examines for the following lockout prevention criteria:

•	IGNITION SWITCH KEY PRESENT signal from the ignition switch

•	DRIVER DOOR OPEN message from the DDM

•	Last door closed locking (LDCL) function active message from the IPC

5. The RFA broadcasts a serial data link command message to lock all of the doors when:

•	The ignition key is out of the ignition switch and if last door closed locking (LDCL) is inactive, as soon as the driver's door is closed.

•	If LDCL is active, as soon as all doors are closed for 5 seconds.

•	The driver's power door lock switch is held in the LOCK position for greater than 3 seconds (Lockout Override).

6. The DDM receives and transmits the command message from the RFA to the PDM and rear door module (RDM).
7. All three modules actuate their door lock motors, thus completing the locking sequence.

The LDCL feature provides a wait state following a lock switch or keyless entry transmitter LOCK command. When a lock command is received, the key must be out of the ignition switch and all door ajar switches must indicate that the doors are closed before any doors are locked. Once all doors close, a 5 second delay is provided for re-entry prior to locking the doors.

The LDCL feature may be activated by the customer through pressing the power door lock switch and then pressing a valid keyless entry transmitter UNLOCK button. Repeating this sequence will toggle the LDCL off and on. LDCL mode active is the standard setting for both keyless entry transmitters as delivered to the dealer.

The automatic door lock (ADL) function provides for locking or unlocking the doors when shifting the transmission in and out of PARK. Personalization selections may be made as follows:

Unless the first mode is selected, the RFA module will receive powertrain control module (PCM) shift select changes over the class 2 data lines. Whenever the left front door is closed, the ignition is in RUN and the gear selector is shifted out of PARK, the RFA module will transmit a class 2 lock doors message to the DDM. The DDM will send this message on to the other door modules over the simple bus interface (SBI) and the modules will lock their doors as programmed. If personalization is selected to do so, the RFA will also unlock the doors when the gear selector lever is put back in to PARK. Refer to Keyless Entry System Description in Keyless Entry.