Memory Seat System Operation

2004 Toyota Matrix XR, FWD, StandardSECTION Memory Seat System Operation
WARNING: This page is about a different car, the 2004 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.

Depressing any of the drivers front door trim panel mounted, memory seat switches sends a hardwired, resistor multi-plexed signal to the drivers door module. The door module then sends a PCI data bus message to the Memory Heated Seat/Adjustable Pedal Module (MHSAPM). The module detects the memory seat switch status via the PCI data bus circuit and energizes the appropriate power seat motors. The programmed software in the MHSAPM allows it to know the location of the seat track by a resistance value generated from the seat track mounted potentiometers. When the correct preset location is achieved the module will de-energize the power seat track motors. The MHSAPM will prevent the seat memory recall function from being initiated if the transmission gear selector lever is not in the Park or Neutral positions, or if the vehicle is moving. These inputs are monitored over the PCI data bus circuit.

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