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Bank 1 downstream O2 sensor problem. My parts changer techs read a code and installed a new sensor (in the wrong spot, changed the bank 2 sensor, gotta love parts changers) told em to change out the right one and let me know if it fixed it. Still didnt work. Scan tool with koeo shows what appears to be a bias line of 455mv on all O2 sensors. Koer and bank 1 downstream stays at 450. Unplugged is the same as well. Unplugged put 12v to the signal wire (purple white) and no change on the scan tool. Suspected open in the wire. Tugged on it and doesnt break. Taken off the conduit and did visual inspections (looks good, no visible damage or green cruddies). I must have missed something but im over here scratching my head. Oh and a new sensor has been installed in the right location already
I double checked the voltage on the signal wire. Koeo and unplugged reads about 430mv. That would suggest that the wire is good and point me in the direction of bad computer. And idk what changed but scan tool will actually spike intermittently. Not by much. Only to about 470 480mv
backprobe the wire at the pcm and read it with a dvom and compare it to the scanner. if the meter shows normal o2 readings then the scanner stays at 450 then id suspect the pcm for sure
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