Ferrari Mailing List: Can faulty crankshaft position sensor trigger O2 sensor codes?

[Larry Bard (larrybard]

After my friend had worked on my 512TR (at his house) I drove it home and observed the 7-12 check engine light. Later in the week I read the error codes, erased them, then ran the car (just warming it up).  Upon starting, the idle had oscillated back and forth, final settling down around 1100 RPM.  And the 7-12 check engine light had reappeared for a brief time when (twice) I fed more gas, increasing the RPMs to a bit above 2k.

The newly generated codes are as follows:
 
  * for 7-12: 1211 "lambda regulation" (which I believe is the oxygen
    sensor) and 1121 "RPM sensor" (which I believe is the crankshaft
    position sensor)
  * for 1-6 (even though the check engine light did not come on for
    those cylinders): 1121 (RPM/crankshaft position)
  
Is it likely that the two codes are related, rather than being traceable to completely independent problems?

I guess I could imagine how a defective crankshaft position sensor -- which I suppose is far less common than a defective 
oxygen sensor -- might affect engine timing and therefore perhaps the oxygen/fuel mixture.

So a defective crankshaft position sensor would also trigger an oxygen sensor code?

Larry