Diagnostic Routine C

Diagnostic Routine C

Diagnostic Overview

Power-Stow Seat Motor and Sensor Functional Test - LH

Refer to Wiring Diagram Set 120, Power Seats for schematic and connector information. Diagrams By Number

Normal Operation and Fault Conditions

The PFSM (Power-Fold Seat Module) supplies voltage and ground to the power-stow seat motor to move the seat to and from the STOW position when selected by the seat control switch. When STOW is selected from NORMAL, the backrest folds forward to release the spring loaded headrest. If an obstruction is detected in the STOW range of movement, the seat stops, reverses movement a few inches and then stops again until the obstruction is removed. When the obstruction has been removed, the seat control switch must be pressed again to reset the request. The seat goes to the power-stow seat motor home position (seat folded and latched to the floor) and then continues with the STOW request. If the PFSM (Power-Fold Seat Module) detects an open or short in the power-stow seat motor circuitry, motor operation is disabled. If a short to ground is present, the motor works in only one direction.

A Hall-effect sensor is located inside each of the power-stow seat motor assemblies to detect power-stow seat motor movement and position to the PFSM (Power-Fold Seat Module). If the sensor does not detect motor movement during a request from the seat control switch, the PFSM (Power-Fold Seat Module) disables the power-stow seat motor output. When the seat control switch is pressed again, the seat moves in short increments indicating a fault with the sensor or circuitry.

Visual Inspection and Diagnostic Pre-checks

Verify good battery condition before diagnosing the PFSM (Power-Fold Seat Module) system. Poor battery condition may interfere with PFSM (Power-Fold Seat Module) operation. If battery voltage drops below 10 volts, seat movement does not start. If battery voltage drops below 8 volts, a started seat movement stops.

To ensure the most accurate service information, portions of this procedure are under development and may not be immediately available at vehicle introduction.