Simple question here, i've researched it for hours and just need confirmation. i need to replace Bank 1 Sensor 1. i know the harness should be black. i do not have a black harness in my car, i have 2 blue ones though. Is Bank 1 Sensor 1 the sensor that goes right into the header closest to the firewall?

http://forums.maxima.org/5th-generat...bs-inside.html

here it looks like it is closer to the cat, instead of the manifold.

 

well i went ahead and replaced the O2 sensor closest to the firewall. replaced it with a NGK sensor, http://www.amazon.com/NGK-24618-Oxyg...7644875&sr=8-1
i am now getting a P0051 code, does any1 know if i 1: replaced the wrong sensor, or 2: replaced it with the wrong 1. the sensor that i replaced appeared to be a "heated" sensor. the sensor in the link doesnt really look like it is.
any help is appreciated, i dont want to continue to pay 90 bucks if they're the wrong 1's. Thank you

 

were you getting a P0031 code? If so Bank 1 Sensor 1 is closest to the firewall and has a light blue connector that ends right behind the intake manifold. You should have been able to access the sensor from the engine bay and reaching down between the engine and firewall.

 

Yeah I was, so that is the sensor that I replaced.I was getting the P0031. Now I'm getting a 51. . .