B1D77 Code - Seat Recliner Position Sensor Circuit

The Memory System is made up of a Memory Seat Module-Driver (MSMD), Memory Switch, Driver Seat Switch, Adjustable Pedal Switch, and multiple Seat Motors and an Adjustable Pedal Motor. The motors each contain a hall-effect position sensor. The hall-effect position sensor provides feedback to the MSMD in relation to the motors position.
The Driver Seat Switch is a Multiplex (Mux) switch which uses set resistance levels for each switch position. These resistances correspond to different voltages which is monitored by the MSMD over two separate circuits. When a voltage change is detected, the MSMD will command the appropriate Seat motor(s) to move the seat in the requested direction as long as the Driver Seat Switch is held in that direction or its stops have been reached.
The Adjustable Pedal Switch is a three position switch (forward, center, rearward). The MSMD monitors the forward and rearward circuits voltage. If a voltage change is detected, the MSMD will command the Adjustable Pedal motor to move the pedals in the requested direction as long as the Adjustable Pedal Switch is held in that direction or its stops have been reached.
The Memory Switch is a Mux switch that is used to set and recall the seat and pedal positions. When a Memory Switch button is pressed, the Driver Door Module (DDM) detects a voltage change and sends a request over the Controller Area Network (CAN) bus circuit to the MSMD to perform the requested command. If the SET button on the Memory Switch is pressed, followed by the 1 or 2 button, the MSMD will store the seat and pedal positions based on the position inputs received from the hall-effect position sensors. If the 1 or 2 button on the Memory Switch is pressed, the MSMD will recall the stored seat and pedal positions for that particular selection and return the seat and pedals to the stored positions. Memory position may also be recalled using a linked FOBIK transmitter. For driver safety, the MSMD will prevent the memory recall function from being initiated if the transmission gear selector lever is not in the Park position or if the vehicle is moving.

• Faulty Seat Recliner Position Sensor
• Seat Recliner Position Sensor harness is open or shorted
• Seat Recliner Position Sensor circuit poor electrical connection
• Faulty Driver Recliner Seat Adjuster Motor
• Faulty Memory Seat Module-Driver (MSMD)