Seating - Memory: Notes
Overview
When the vehicle is equipped with the programmable/recall memory option, the driver power seat is controlled by the DSM. The DSM is located on the driver seat track.
This system allows automatic positioning of the driver seat to 1 of 3 programmable positions. For information on programming memory positions or recalling a stored memory position, Refer to Memory Position Programming .
System Operation
System Diagram
Network Message Chart
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Drivers seat memory command | DSM | When one of the 3 memory set switches are activated, the DSM sends this information to the BCM to initiate a personality recall command. |
Network Message Chart
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Selector lever (PRNDL) status | PCM | Provides the status of the selector lever position. When the ignition is on, the gear selector must be in NEUTRAL or PARK to carry out a memory recall operation. |
| Key-in-ignition status | BCM | Provides the ignition position. This input is used for the easy entry and easy exit feature. |
| Personality recall | BCM | When the personality recall command is received from the BCM, the DSM stores or recalls the associated memory seat position (1, 2 or 3). If an RKE transmitter has been programmed to a memory position, this input is used to recall the associated memory seat position. |
Memory Recall
The NEUTRAL position of the driver seat control switch is at a ground state through the seat control switch normally-closed contacts. The driver seat control switch provides voltage to the DSM only when activated. A voltage input causes the DSM to power the appropriate motor until the input is removed. Ground is the normal state of the motor circuits through the DSM. The DSM internally switches the appropriate circuit from ground to voltage to operate the motors.
As the seat is adjusted, the DSM monitors the motor position sensors to record the current seat position. The DSM removes voltage from the motor upon termination of the seat control switch input or if the DSM does not detect movement from the motor while monitoring the position sensor during a memory recall operation.
RKE Transmitter
A RKE transmitter can be used to recall previously set memory positions but must first be associated to that memory position. The transmitter associated with personality 1 is capable of recalling memory position 1 only. Similarly, the associated personality 2 transmitter can recall only memory position 2.
DSM Hard Stop/Soft Stop
The DSM has the ability for soft stops both at the upper and lower limits on all axes of the driver seat. When an axis reaches the hard stop and the switch is held for approximately one second, it then backs up 180 ms and establishes the soft stop for that axis in that direction. The DSM uses this back up strategy to check sensor integrity any time movement has stopped prematurely due to a sensor failure or obstruction.
A hard stop occurs when one of the memory seat track axes or backrest recline physically reach the end of travel and can go no further. A soft stop occurs when the seat stops before physically reaching the end of travel. The hard stop is set by seat design and cannot be changed or adjusted. The soft stop is set by the DSM. The seat track axes are forward/rearward, front up/down and rear up/down. The backrest axis is recline forward/backward. To prevent unnecessary stress on the seat and motors, the DSM sets soft stop positions, 2 for each moving axis. The DSM uses a preset distance from the hard stop to determine where the soft stop occurs. When an axis reaches the hard stop and the switch is held for approximately one second, the DSM establishes the soft stop for that axis in that direction.
Setting the Soft Stop
Use the following procedure once a new seat track or DSM has been installed. During the setting procedure, if the seat track stops before the end of travel has been reached, the DSM has stopped at a previously set soft stop. To set the new soft stop, release the seat control switch and immediately press again in the same direction until the seat track stops at the hard stop for that given direction.
Turn the ignition ON.
- Press the seat control switch horizontal button forward until the seat track stops.
- Keep the horizontal button pressed forward for one second after the seat track reaches its forward end of travel. The horizontal forward soft stop has been set, release the switch button.
- Repeat the previous steps for all seat track axes in both directions.
Easy Entry, Easy Exit
The easy entry/exit feature is a function of the DSM that moves the driver seat back approximately 50.8 mm (2 in) (unless seat is already positioned at or near the end of travel) when the ignition key is removed from the ignition switch. The DSM receives a key-in-ignition status over the MS-CAN and operates the driver seat rearward. The DSM cancels this operation if a valid input command is received from the driver seat control switch, memory set switch, exterior mirror control switch or if the function has been disabled.
The DSM records the current seat positions before operating the seat for an easy exit operation. This recorded position returns the seat to this position on the easy entry operation. During easy entry operation, the seat is returned to the position previous to the easy exit operation. Easy entry operation is cancelled if a valid input command is received by the DSM.
The easy entry/exit feature can be enabled/disabled on the message center. For information on the message center, refer to the Owner's Literature.