Hi, I got a service engine light and rough idle with code P0131 (O2 Circuit Low Voltage Bank 1, Sensor 1) which my Haynes Repair Manual tells me is the upstream oxygen sensor. When I go to RockAuto, there are multiple brands (NTK, Bosch, Denso, Walker Products) and each has California and federal emission variants. I took the following picture of the sticker under the hood which says “U.S. EPA: For sale only in states with California emissions standards.”
I just want to confirm I should be using the California variant and what brand do you recommend?
https://i.imgur.com/8MwHuIA.jpg
If you are in California, get the California compliant one. If you are not, im California. Get whatever one you want
NTK and Denso are best for a Nissan. That said, verify the wiring first. Unplug the sensor. The car should toss codes for B1S1 Voltage high, heaters etc. If it does, then sensor is the issue. If it doesn’t, look for a short in the wiring. A “low voltage” code typically indicates a short to ground, whereas a “voltage hi” code usually indicates a short to battery or an open(broken) circuit.
Hope this helps