Memory Seat Module - Operation

OPERATION

The Memory Seat Module (MSM) receives battery current through a circuit breaker in the Totally Integrated Power Module (TIPM) so that the power seats remain operational, regardless of the ignition switch position. When the driver memory seat switch control knob is actuated, a resistance signal is sent to the MSM via the Controller Area Network (CAN) bus circuit. The MSM is responsible for the 12V battery feed and ground path to the power seat adjuster motor. The adjuster motor operates to move the power seat adjuster mechanism through its drive unit in the selected direction until the switch is released, or until the travel limit of the adjuster is reached.

The MSM receives memory set/position switch input through the CAN bus circuit. The MSM also receives hard wired input from the hall effect sensors, mounted on each of the driver power seat adjuster motors and the driver side view mirror motor. The programmed software in the module allows it to know where the seat/mirror is located in its designed travel by a pulse count generated from the hall effect sensors. This way, when the memory switch is depressed the module will power the seat adjuster/mirror motors until the correct preset location is achieved. The module will prevent the seat memory recall function from being initiated, if the transmission gear selector lever is not in the Park position, or if the vehicle is moving. These inputs are monitored over the Controller Area Network (CAN) bus circuit by the MSM.

A memory setting is saved by pressing the "set" button, then pressing either the memory "1" or "2" button within 5 seconds of pressing the "set" button.

A memory setting is recalled by pressing either the memory "1" or "2" button, or by pressing the unlock button on a "linked" Remote Keyless Entry (RKE) transmitter (also known as the key fob).

For driver safety, memorized settings can not be recalled if the transmission is in a position other than Park or the seat belt is latched.

The Electronic Vehicle Information Center (EVIC) serves as the user interface for the memory system. It displays memory system status messages and provides the user with the means for enabling and disabling the many customer programmable features available on the vehicle, including those for the memory system.

Electronic Vehicle Information Center - Operation for additional information on the EVIC.

The MSM performs the following functions:

- Positions the driver power seat (vertical, horizontal, and recliner positions).
- Positions the power adjustable pedals.
- Sends the memory save or recall (#1 or #2) command over the CAN data bus circuit to the other memory system components, radio station pre-sets and power mirror positions.
- Provides for "linking" the key FOBs to memory.
- Provides for the easy entry/exit feature.
- Provides the tilt mirrors in reverse feature.

When a memory button is pressed (#1 or #2) on the memory switch, the left Front Door Module (FDM) sends a recall message to the MSM. The MSM will then position the memory system components to the preprogrammed location/setting. When the Remote Keyless Entry (RKE) Transmitter button is pressed, depending on which transmitter (#1 or #2), the SKREEM (RKE Receiver) sends the recall request and FOB number (#1 or #2) data message. This RKE transmitter function depends on if the MSM is programmed to trigger the recall (linked FOBs).

A memory setting is saved by pressing the "set " button, then pressing either the memory "1" or "2" button within 5 seconds of pressing the "set" button.

A memory setting is recalled by pressing either the memory "1" or "2" button, or by pressing the unlock button on a "linked" Remote Keyless Entry (RKE) transmitter.

For driver safety, memorized settings can not be recalled if the transmission is in any position other than park or the seat belt is latched.

A key FOB is "linked" to a memory setting by pressing the "set" button and then pressing either the memory "1" or "2" button within 5 seconds of pressing the set button, and then, with the key removed from the cylinder, pressing the "lock" button on the selected key FOB.

The memory system "Easy Entry and Exit" feature provides the driver with more room to enter or exit the vehicle. This is a customer programmable feature of the overhead console, Electronic Vehicle Information Center - Description. When the seat is in a memorized position, it will move rearward 55 millimeters or to the end of its travel, whichever occurs first, when the key is removed from the ignition switch lock cylinder. A lock out zone of 60 millimeters has been established to protect rear passengers from injury. If the memorized seat position is within the lock out zone the Easy Exit/Entry seat glide feature is disabled. The seat will return to the memory position when the driver turns the vehicle's ignition switch out of the LOCK position.

The memory system "Tilt in Reverse" feature tilts the outside mirrors down a fixed, incremental angle when the vehicle is shifted into REVERSE with the ignition switch in the RUN position. This feature provides the customer with a better view of the ground and vehicle in the area of the rear tires when backing up. The mirrors move back to their previous position when the vehicle is shifted out of REVERSE.

The memory system "learns" the seat and adjustable pedal motor maximum end positions when the motor reaches the limit of travel in any direction and stalls. Subsequently, movement will stop just short of that position to avoid extra stress on the motors and mechanisms. If the system learned a maximum position as a result of an obstruction, as for instance if a large object was placed on the floor behind the seat, the system can relearn the "true" maximum position through manually operating the power seat after the obstruction is removed.

NOTE: It is normal for the power accessories contained in the memory system to stop at the maximum "learned" position and then continue to the "true" maximum position when the control switch is released and then applied in the same direction a second time.

Certain functions and features of the memory system rely upon resources shared with other electronic modules in the vehicle over the Controller Area Network (CAN) bus. The CAN bus allows the sharing of sensor information. This helps to reduce wire harness complexity, internal controller hardware, and component sensor current loads. At the same time, this system provides increased reliability, enhanced diagnostics, and allows the addition of many new feature capabilities. For diagnosis of these electronic modules or of the CAN bus, the use of a scan tool and the proper diagnostic information are needed.