Memory Seat Module - Operation

OPERATION

The Memory Seat Module (MSM) receives battery current through a fuse in the Totally Integrated Power Module (TIPM). The memory system remains operational, regardless of ignition position. When a driver memory seat switch button or FOBIK transmitter button (when programmed) is pushed, signal is sent to the MSM over the Controller Area Network (CAN) bus. The MSM is responsible for the 12 volt Direct Current (DC) feed and ground path to the power seat adjuster motors and to the other memory system components.

The MSM also receives hard-wired input from the hall effect sensors, mounted on each of the driver power seat adjuster motors, driver side view mirror motors and power adjustable steering column motors, when equipped. The programmed software in the MSM allows it to know where the driver seat, mirror and steering column are located in there designed travel by a pulse count, generated from hall effect sensors. This way, when a memory seat switch is pressed the MSM will power these components until the correct preset location is achieved. The MSM will prevent the seat memory recall function from being initiated, if the transmission gear selector is not in the Park position. These inputs are monitored over the CAN bus by the MSM.

A memory setting is saved by pressing the "Set" button, then pressing either the memory "1" or "2" button within five 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" FOBIK transmitter.

The MSM performs the following functions:

- Positions the driver power seat (fore/aft, up/down, tilt and recline positions).
- Sends the memory save or recall (number 1 or number 2) command over the CAN data bus circuit to the other memory system components, radio station pre-sets and power mirror positions.
- Provides for the easy entry/exit feature.

When a memory button is pressed (number 1 or number 2) on the memory seat switch, it provides resistive signal to the MSM. The MSM will then position the driver seat to the pre-set location. When a FOBIK transmitter button is pressed, depending on which transmitter (number 1 or number 2), the WIN/SKIM receiver sends the recall request and FOBIK number (number 1 or number 2) data message. The FOBIK transmitter function depends on if the MSM is programmed to trigger the recall (linked FOBIKs).

A FOBIK 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, then by pressing the "lock" button on the selected FOBIK.

The memory seat system "Easy Entry and Exit" feature provides the driver with more room to enter or exit the vehicle. When the driver seat is in a memorized position, it will move rearward 55 millimeters (2.2 inches) or to the end of its travel, whichever occurs first, when the key is removed from the ignition switch lock cylinder. This is a customer programmable feature. The seat will return to the pre-set position when the ignition is pressed to RUN.

The memory seat system "learns" the seat, mirror and column motors 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 seat system rely upon resources shared with other electronic modules in the vehicle over the 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, the memory seat system provides increased reliability, enhanced diagnostics and allows the addition of new feature capabilities.

NOTE: Anytime a new Memory Seat Module (MSM) or a driver power seat motor or seat track is replaced, the MSM must be cleared of all learned parameters using a scan tool and the Power Seat System Verification test must be performed.

The use of a scan tool is needed for diagnosis of the MSM, CAN bus and other electronic modules Testing and Inspection.