B2120

DTC B2120 Lumbar Up/Down Sensor Failed:

CIRCUIT DESCRIPTION
The Memory Seat Module (MSM) receives inputs from the lumbar position sensors during memory recall and memory set functions. The potentiometers in the position sensors vary in resistance as the motors move the lumbar support.. The MSM receives a variable voltage input depending on the resistance of the potentiometer. During memory set, the MSM records the voltage across the lumbar potentiometers. During memory recall, the MSM moves the lumbar motors until the voltage across each potentiometer matches the voltages stored. During normal operation, the lumbar position sensors are tested against the out-of-range limits.

CONDITIONS FOR SETTING THE DTC
^ These DTCs set only if DTC MSM B1982 or DTC MSM B1983 is not current. For the diagnosis of these DTCs, refer to DTC B1982 Source/Battery Voltage High or DTC B 1983 Source/Battery Voltage Low.
^ The MSM sets the appropriate DTC whenever the MSM detects that the sensor input voltage is not within 0.25-4.75 volts. Testing and Inspection

ACTION TAKEN WHEN THE DTC SETS
When a position sensor DTC is set as current, the MSM disables the affected motor during the memory recall operation. The motor remains enabled for manual positioning.

CONDITIONS FOR CLEARING THE DTC
The MSM does not detect the position sensor failure during the last monitoring cycle.

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
1. This step tests for proper reference voltage to the suspect position sensor.