After installing my Doug Thorley header last weekend I got a P0125. After Googling, I came up with a bunch of things. But, after searching on here, Toyota had their own reason for this code... the front O2 sensor / A/F sensor. Well, I ordered a new Denso from URD. I cleared the code via ScanGauge and put in the new sensor. Within 5 mins of driving the CEL came back on.
Is there something that I may not know, that I may have overlooked? Or do I just need to continue down the list until the CEL goes away?
Oh, I didn't disconnect the battery. I simply cleared it via ScanGauge. Could that be the/an issue?
Edit : Disconnected battery. Same issue.