The power door lock subsystem comprises the following components:
• | Class 2 serial data link |
• | Door lock actuators (motors/manual levers) |
• | Driver door module (DDM) |
• | Left front power door lock switch |
• | Passenger door module (PDM) |
• | Remote function actuator (RFA) module |
• | Right front power door lock switch |
• | Simple bus interface (SBI) |
Remote Function Actuator (RFA) Module
The remote function actuator (RFA) module is the door lock master device.
This means the RFA has final control over whether or not all doors will lock
or unlock under power. The RFA will not allow any doors to be power locked
unless the key is out of the ignition and the doors are all closed as indicated
by the door jamb switches.
Driver Door Module (DDM)
The driver's door module (DDM) directly controls the driver's door lock
actuator motor. The DDM receives and forwards driver's door switch lock request
messages to the remote function actuator (RFA) via the serial data link.
The RFA receives the request message and examines it for lockout prevention
criteria. If the conditions are proper, the RFA sends a lock or unlock
command message back to the DDM. 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 a simple bus interface (SBI) line.
The DDM also contains a class 2 serial interface which communicates
with other vehicle system modules. The LH front door power window and the
outside power mirror are also controlled through the DDM. Battery voltage
is always applied to the DDM through the RAP circuit breaker located
in the Underhood Maxifuse® Block.
Passenger Door Module (PDM)
The passenger's door module (PDM) controls the passenger's door lock
actuator. The PDM also monitors the passenger's power door lock switch. The
RH front door power window and outside power mirror are also controlled
through the PDM.
Rear Door Module (RDM)
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.
Power Door Lock Switch
The power door lock 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 LH power door lock switch feeds the LH front power window
switch which then transmits a switch activity message to the DDM.
Passenger Power Door Lock Switch
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).
Door Lock Actuators
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 switch is operated, driving the door
lock lever in or out. The rear doors have no power lock buttons, only manual
lock levers. The power door lock switches are generally closed for just
a moment. If the power door lock switches are held closed for too long,
an electronic 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. Each door lock actuator
assembly contains a manual door lock lever. 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 and move the lock actuators. When the driver's door
key cylinder is turned, all doors will unlock. The key locks and manual
lock levers will still work if electrical power is lost.
Class 2 and Simple Bus Interface (SBI) Serial Data Links
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.
Lock/Unlock Sequence
When the passenger power door lock switch is pressed, the following
events occur:
- The passenger door module (PDM) will directly sense actuation
of the passenger door power lock switch.
- The PDM will send a serial data link message to the driver's door
module (DDM) requesting that the doors be locked.
- The DDM receives and forwards the lock request message to the
remote function actuator (RFA) via a serial data link.
- The RFA receives the request message and examines for the following
lockout prevention criteria:
• | IGNITION SWITCH KEY PRESENT signal (CKT 80) from the ignition
switch |
• | DRIVER DOOR OPEN message from the DDM |
• | Last door closed locking (LDCL) function active message from the
IPC |
- 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). |
- The DDM receives and transmits the command message from the RFA
to the PDM and rear door module (RDM).
- All three modules actuate their door lock motors, thus completing
the locking sequence.
Last Door Closed Locking (LDCL) Feature
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 doorjamb switches must indicate
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.
Automatic Door Locks
The automatic door lock (ADL) function provides for locking or unlocking
the doors when shifting the transmission in and out of PARK. Customized selections
may be made as follows:
- No automatic door lock or unlock
- Automatic all door lock when shifter moves out of PARK. No automatic
door unlock
- Automatic all door lock when shifter moves out of PARK. Automatic
driver door unlock when shifter moves into PARK
- Automatic all door lock when shifter moves out of PARK. Automatic
all door unlock when shifter moves into PARK.
The driver's door module (DDM) communicates with the remote function
actuator (RFA) module over the class 2 data link. The RFA module receives
powertrain control module (PCM) shift select changes. 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 Operation
in Keyless Entry.