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)
On a 2000 Nissan Sentra, the oxygen (O2) sensors are typically located in two places: one is positioned in the exhaust manifold before the catalytic converter (upstream O2 sensor), and the other is located after the catalytic converter (downstream O2 sensor). To access them, you may need to raise the vehicle and work underneath, as they are threaded into the exhaust system. Be sure to disconnect the electrical connectors before attempting to remove the sensors.
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
The number of O2 sensors in a Nissan Sentra typically depends on the model year and engine type. Most modern Sentra models have two O2 sensors: one located before the catalytic converter (upstream) and one after it (downstream). However, some specific configurations or older models may have different arrangements. Always check the vehicle's manual or specifications for precise information.
with your hands and some tools
Gas mileage also went down and I just replaced o2 sensors.
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
It is in the exhaust pipe right after the exhaust manifold.