Memory Positioning Systems: Description and Operation

MEMORY SYSTEM
The memory system consists of power driver's seat, power mirror, adjustable pedals and radio presets. The Memory Seat/Mirror/Adjustable Pedal s Module (MSMAPM) is located under the driver's seat. It receives input from the following: driver's manual 8-way seat switch, driver's seat position sensors, PCI bus circuits, and the power mirror sensors. The module uses these inputs to perform the following functions: position the driver's memory seat, both exterior mirrors (during recalls), both pedals, and send/receive the memory system information over the PCI bus.

The Memory Set Switch is wired to the Body Control Module (BCM). A button (either #1 or #2) pressed on the set switch causes the BCM to send a message to the MSMAPM which in turn will send a motion status message back to the BCM. If the message from the MSMAPM indicates no current motion, the BCM will send a recal message to the module. The MSMAPM will set the seat, exterior mirror, pedals, and radio to the presets for the indicated driver.

If any one of the memory controlled systems is inoperative from its manual switch, use the schematics and diagnostic information to correct the concern. This manual addresses the memory problems only and it is assumed there is not a basic component failure.

POWER SEAT
The memory power seat provides the driver with 2 position settings for the driver's seat. Each power seat motor is connected to the MSMAPM with two motor drive circuits. Each circuit is switched between battery and ground. By being able to bi-directionally drive the circuits, the MSMAPM controls the movement of the motors based on input from the power seat switch or from the position sensors when performing a memory recall. Each motor contains a potentiometer to monitor the seat position. To monitor the position of the motor, the MSMAPM sends out a 5-volt reference on the sensor supply circuit. The sensor is grounded back to the module on a common ground circuit. Based on the position of the sensor, the MSMAPM monitors the voltage change through the sensor on a separate signal circuit.

The MSMAPM stores the input value of each of the four seat potentiometers in memory when the system requests a set. The driver can initiate a memory recall, using either the door mounted memory switch or the RKE transmitter (if the remote linked to memory feature is enabled via the EVIC). When initiated, the MSMAPM adjusts the four seat sensors (by using the motors) to match the memorized seat position data.

For safety, the memory seat recall is disabled by the MSMAPM when the vehicle is out of park position or if the speed is not zero. Any obstruction to seat movement over a 2-second delay will cause the seat to stop moving in which case a stalled motor would be detected by the MSMAPM and the corresponding seat output would be deactivated. However, if the object obstructing the seat is removed, the seat will function normally again.

MEMORY MIRROR
The driver sideview mirror contains vertical and horizontal bi-directional drive positioning motors and position sensors. The MSMAPM provides a 5-volt reference on the signal circuit to each position sensor. The sensors share a common ground circuit. The MSMAPM monitors the position of the mirror motors by measuring the voltage on each signal circuit. When a memory position is set, the MSMAPM monitors and stores the position of the outside mirror. The MSMAPM adjusts the mirror to the appropriate positions when a memory recall message is received from the RKE or is requested from the memory set switch.

The power mirror switch during non-memory operation operates the mirror independently of the MSMAPM.