Hello all, new to the forum, not new to Honda's except the one my son just purchased. It's a civic si hatchback that is apparently rare in the civic world. Has a SES light on, so I scanned it and got 2 codes, P1167 and P1166. So I went to my current data and noticed the downstream O2 is switching voltage, while the upstream O2 is at 0 volts and doing nothing. So I cleared the codes, light came back on about 5 seconds later, but this time only had the P1166 code. Wondering if these models have wiring issues or if it's probably just the upstream O2. Car is in nice shape, garage kept, and was elderly and lady owned with 126k miles.

 

Anybody have any ideas?

 

Toss a quality (NTK or OEM) upstream o2 sensor at it and see what happens?