2010 Cadillac CTS Sedan AWD V6-3.6L Page 638
Circuit/System Description
The memory seat module (MSM) controls the seat, recline, lumbar, and steering column motors via half bridges that are divided into 2 groups that
are connected to separate power rails internal to the module. The MSM connects all of the motor control circuits on each power rail to a common
reference point whenever they are not in operation. This reference point is biased to approximately 2.5 volts. The MSM checks to see if this
reference voltage is shorted to ground or battery before enabling any seat, lumbar, or steering column motor.
Conditions for Running the DTC
The MSM must be powered.
Conditions for Setting the DTC
B3920 01
The voltage on any power rail 1 motor control circuit exceeds 2.78 volts for 100 ms.
B3920 02
The voltage on any power rail 1 motor control circuit is below 1.47 volts for 100 ms.
B3921 01
The voltage on any power rail 2 motor control circuit exceeds 2.78 volts for 100 ms.
B3921 02
The voltage on any power rail 2 motor control circuit is below 1.47 volts for 100 ms.
Action Taken When the DTC Sets
The MSM will not allow operation of any motor on the power rail for which the DTC was set.
