My 99 Legacy Brighton Wagon 2.2L EJ22(California Emissions) CEL code P1133. It is translated to HO2S High input circut fault. I have chaged out the part (the oxegen sensor) twice, the code will not clear out. The Volts should fluctuate roughly .05 - 1.0v, usually les than 1.0v i.e; .65-.95v. at any rate, the my live data scanner shows the volt reading as 3.764v! This is the up-stream ho2s. (pre-cat) The down stream ho2s reads a normal input of .66-.88v respectively. The first sensor replacment was a cheapo universal the pcm would not recognize/read the new sensor. The second sensor was used from another 99(CA EM) Same thing P1133 high output. I am kinda stuck here. Not sure how to proceed. Could it be the connector wires from the sensor plug to the PCM? Any TSB or MODIS (snap-on's scanner) troubleshooting say that Tech's in the field report that 9 times out of t10 the sensor is failing and not the PCM or anything in between. Has any one ever encountered this or something similar before? Any Ideas?

The P1133 code is for a problem in the heater circuit of the O2 sensor. If the ECU/PCM ''thinks'' it can't control the heater properly, it will set the code. The high voltage you measured for the sensing element is apparently not a concern, as others have reported proper operation as long as the O2 sensor/heater and wiring are good. Although not specific to your model/year, see the following threads for further insight:

http://www.ultimatesubaru.org/forum/showthread.php?t=66744

http://www.ultimatesubaru.org/forum/showthread.php?t=98800