I have a problem with my front right O2 sensor. The ECU is throwing codes: 5-3 (front right O2 sensor malfunctionj) and 3-7 (closed loop control). This mess occurred after an engine shampoo. I am hoping that the power washing caused a harness or plug to come loose that I can quickly reattach and in turn fix the problem. I being a mechanical moron cannot seem to locate the plug/harness which connects the O2 sensor. Would someone please be able to give me some detailed directions in my quest to locate this critter? Thank you in advance for all your help.

 

There are two O2 sensor connectors underneath the hood. The one for the front, or left bank, is located next to the engine dipstick (towards the battery)...it is the larger connector there if you have a 95-98 Maxima. If you have a 99, it's one of the four connectors in front of the engine.

The rear bank (right bank) connector is located on the passenger side corner of the engine bay near the power steering fluid reservoir. You can tell it is an oxygen sensor wire because the wire leads down to the actual sensor itself which is mounted just downstream of the exhaust manifolds.