So I missed yet another tuning appointment because I'm seeing the P0328 code. The Subaru troubleshooting section of the manual says to check the circuit resistance which needs to be more than 400kohm. I measure 559. Then, check the voltage on the ECM pin to be less than 2v. I get 2.46. The wiring itself has continuity with no measurable drop. Hmmm. About all they say from there is to check wiring and connections which seem ok. I bought another knock sensor - this one only has 3K miles on it and is clocked correctly and torqued to spec, and the new one (OEM of course) measures exactly the same - 559kohm.

I'm going to put the new one on because, well why not, but I'm not feeling good that this will cure it. What does the collective Subaru wisdom have to say?

Ed