it's the thing sticking out of the exhaust with a wire attached to it...if it doesn't have one and it's causing problems then you probably have an aftermarket exhaust and you need to weld a bung on the exhaust to attach one
Replace the Downstream O2 sensor (after the catalytic converter)
o2 sensors are in the exhaust Usually in front of the catalytic converter near or in the exhaust manifold.
Replace the Downstream O2 sensor (after the catalytic converter)
The are two o2 sensors in an 04 Sentra. One is called the front sensor, and it is in the engine compartment, in the exhaust manifold. The other, the rear one, is in the exhaust pipe under the car, past the catalytic converter.
check your exhaust system there should be a wire running in to your exhaust tat is your o2 sensor good luck There are two o2 sensors, one in the engine and one coming out of the Cat Converter in the exhaust system.
Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)symptomsOther than the MIL light illuminating you may not notice any performance issues.causeA short in the O2 sensor heater circuit or the sensor itselfA faulty O2 sensor heaterWiring or connectors are broken or frayed to the sensor or relayBad PCM or ECMThe fixCorrect wiring short or loose connector found in inspection.and/orReplace the bank 1 sensor 1 O2 sensor
with your hands and some tools
I found this great site about Nissan O2 and its location to fix.. http://maxima.theowensfamily.com/tsb/index.asp?year=2000&tsb=none Search for NTB02-051a All O2 Sensor Replacements Thanks... Jim
Gas mileage also went down and I just replaced o2 sensors.
It is in the exhaust pipe right after the exhaust manifold.
o2 sensor
If bank 1 and bank 2 sensor bad car won't start