Hi George
Your almost there. Siemens like to use 'active inductive' sensors in some applications,(V/hall Simtec was one-remember that?).You are measuring the output from the ecu to the sensors, you would have to look at the output from the ecu and the sensor response on another channel to figure anything out(there is a phase shift in the sinewave) but it's still difficult to figure.
There are two windings in each sensor, resistances 0.5ohm and12ohm in each. Ensure screened cable is good. (and oe sensors).
Ed Kaps