Hey guys, I have an 03 V8 4runner.
I was about to install a Doug Thorley y-pipe onto stock headers when I stripped an exhaust stud on the passenger side flange between the y-pipe and the header. No big deal, I ordered a new stud and hardware to swap out. Fast forward to today, I couldn't for the life of me get the stud out of the rusty flange and decided to put off the install for further down the line.
Driving it to work, I got a CEL the code P0051 (which I have never gotten before) so I attributed to the small exhaust leak I made that is right before the downstream 02 sensor. The code, however, is for Bank 2 Sensor 1, the upstream sensor (???) I put a quick bead of weld on the flange to close the leak and plan to use some exhaust putty/tape to seal it and see if the code goes away, but why would I get an upstream code when all I messed with was the area after the primary catalytic converters?
The full code is: P0051 H02S Heater Control Circuit Low Bank 2 Sensor 1
It would just be an insane coincidence that the upstream sensor died when I was doing this job. Also, the 4Runner runs perfect, leading me to believe it is probably not the upstream A/F sensors. I guess this is what I get for fixing something that wasn't broken
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Major Parts List:
Energy Suspension, full front end rebuild, 885& Toytec, SPC upper arms, dual-amped 7 speaker stereo, 5100's, rear swaybar delete courtesy of rust, v6 junkyard skidplates and a lot of elbow grease