DTC B2120: Lumbar Up/Down Sensor Failed (Am3): Description

Memory Seat Module (MSM) receives inputs from lumbar up/down position sensor via lumbar massage module during memory set and memory recall. As motor moves seat, potentiometers in position sensor varies in resistance. MSM receives a variable voltage input depending on resistance of potentiometer. During memory set, MSM records voltage across all seat and lumbar potentiometers. During memory recall, MSM moves motors until voltage across each potentiometer matches stored voltages. During normal operation, position sensors are checked against out-of-range limits. DTC B2120 will not set if DTC B1982 or B1983 is current. MSM will set DTC B2120 when it detects the sensor input voltage is out of range (less than 0.25 volt or greater than 4.75 volts). When DTC B2120 is set, MSM will disable suspect motor during memory recall and easy exit functions. Motor will remain enabled for manual positioning. DTC B2120 will clear when MSM does not detect position sensor failure during last monitoring cycle.