B2120

DTC MSM B2115-B2120:

CIRCUIT DESCRIPTION
The Memory Seat Module (MSM) receives inputs from the seat and lumbar position sensors during memory recall, memory set, and easy exit functions. The potentiometers in the position sensors vary in resistance as the motor moves the seat and' 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 all seat and lumbar potentiometers (only seat voltages are recorded for easy exit). During memory recall, the MSM moves the seat and lumbar motors until the voltage across each potentiometer matches the voltages stored. For the easy exit function, the MSM moves only the seat motors until the voltages match what the MSM has recorded in memory for the easy exit. During normal operation, the seat and lumbar position sensors are checked against out-of-range limits.

CONDITIONS FOR SETTING THE DTC
^ These DTCs will set only if DTC MSM Bl982 or DTC MSM Bl983 is not current.
^ The MSM will set the appropriate DTC any time it detects a position sensor out-of-range.
^ The MSM will set the appropriate DTC any time it detects the sensor input voltage out-of-range (less than 0.25 volts or greater than 4.75 volts).

ACTION TAKEN WHEN THE DTC SETS
When a position sensor DTC is set as current, the Memory Seat Module (MSM) will disable the affected motor during memory recall or easy exit operations. The motor will remain enabled for manual positioning.

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

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
1. This test checks for proper reference voltage to the suspect position sensor.