2001 Buick LeSabre jerks at low rpms

some times at low RPM car will jerk when staring to move from stop or rounding a corner. 2001 buick lesaber , shows code p1811c

This explains what’s happening.

Tester

its very hard to pin point the problem unless you take apart the transmission and here is a very good video on how to do it , personally I wouldnt.