• Programmable Communications Interface (PCI)
data bus circuit
• Circuit breaker
The memory seat system utilizes all the compo-
nents listed above and the following major compo-
nents:
• Memory Set Switch Assembly
• Electronic Vehicle Information Center (EVIC)
• Power Seat Track and Potentiometers
Refer to Wiring for complete circuit diagrams. Fol-
lowing are general descriptions and operations for
the major components in the power seat and memory
seat systems.
DESCRIPTION - MEMORY SYSTEM
The memory system is capable of storing two dif-
ferent position settings for the outside rearview mir-
rors, driver seat and foot pedals and up to twenty
(ten AM and ten FM) radio station presets. The
driver door module (DDM) is the memory system
master, it lets the other modules in the vehicle know
if the vehicle is equipped with the memory system. It
also makes the requests to the other modules to set
or recall their specific settings. The driver door mod-
ule stores and recalls the driver outside mirror posi-
tion. The PDM stores and recalls the passenger
outside mirror position. The radio stores and recalls
the preset stations and the memory heated seat
adjustable pedal module (MHSAPM) stores and
recalls the adjustable pedals and driver seat posi-
tions.
The memory system will automatically recall all of
the previously set “positions” when the corresponding
numbered one (1) and two (2) buttons of the memory
switch are depressed, or when the doors are unlocked
using the Remote Keyless Entry (RKE) transmitter.
If the remote link to memory feature is enabled
through the EVIC, and the key fob has been linked
(pressing SET then one (1) or two (2) on the door fol-
lowed by depressing the lock switch on the key fob)
depressing the unlock switch on the RKE fob will
move the seats, pedals, mirrors and radio stations to
the
linked
position.
The
Body
Control
Module
enables the customer programmable features that
are displayed on the EVIC display, in the cluster.
The memory system also has a customer program-
mable easy exit feature that will move the driver
seat rearward 55 millimeters (two inches) or to the
end of its travel, whichever occurs first, when the key
is removed from the ignition switch lock cylinder.
Certain functions of the memory system rely upon
resources shared with other electronic modules in the
vehicle
over
the
Programmable
Communications
Interface (PCI) data bus network. The PCI data bus
network allows the sharing of sensor information.
This system provides increased reliability, enhanced
diagnostics, and allows the addition of new feature
capabilities. For diagnosis of the electronic modules
or of the PCI data bus network, the use of a DRB
III
t scan tool and the proper Diagnostic Procedures
manual are recommended.
Electronic modules that may affect memory system
operation are as follows:
• Memory Seat Adjustable Pedal Module
(MSAPM) or Memory Heated Seat Adjustable
Pedal Module (MHSAPM) - Refer to Memory
(Heated) Seat Adjustable Pedal Module in the Elec-
tronic Control Module section for more information.
• Body Control Module (BCM) - Refer to Body
Control Module in the Electronic Control Module sec-
tion for more information.
• Driver Door Module (DDM) - Refer to Driver
Door Module in the Electronic Control Module sec-
tion for more information.
• Passenger Door Module (PDM) - Refer to
Passenger Door Module in the Electronic Control
Module section for more information.
• Electronic
Vehicle
Information
Center
(EVIC) - Refer to Electronic Vehicle Information
Center in the Overhead Console System section for
more information.
• Powertrain Control Module (PCM) - Refer to
Powertrain Control Module in the Electronic Control
Module section for more information.
• Radio Receiver - Refer to Radio Receiver in
the Audio System section for more information.
Refer to Remote Keyless Entry System in the
Power Locks section for more information on the
RKE system.
OPERATION
OPERATION - POWER SEAT SYSTEM
The power seat system receives battery current
through a circuit breaker, located in the Integrated
Power Module. The power seat system is designed to
function regardless of the ignition switch position.
A low-voltage cut-off feature is designed into the
power seat system. If the vehicle battery voltage
drops below a certain set-point (approx. 11.5v), the
power seats will not operate. This is necessary to
prevent the vehicles battery from being discharged to
the point that the vehicle may not start and run.
Under normal conditions this feature will be trans-
parent.
When a power seat switch control knob(s) is actu-
ated, a hard-wired resistance signal is sent to the
appropriate door module. The door module then
sends the request to the Memory Heated Seat Adjust-
able Pedal Module (MHSAPM) via the PCI data bus
circuit. The MHSAPM is responsible for controlling
the 12v battery feed and ground path to the selected
CS
POWER SEAT SYSTEM
8N - 25
POWER SEAT SYSTEM (Continued)