Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Bad oxygen sensor › Reply To: Bad oxygen sensor February 18, 2021 at 7:13 pm #988934 fredParticipant Turns out Bank 1 sensor 2 was bad. Bank 2 sensor 2 is good. So I only had one sensor to replace. I just bought a new diag tester with graphing capability which really helped figure it out.