Replacing Maxima O2 Sensors
Upstream O2 sensors:
Necessary tools:
*3/8″ drive ratchet
*22mm O2 sensor removal ratchet (rent it from Autozone for free)
*OEM upstream O2 sensor(s)
*Anti-seize
*PB Blaster (or WD40)
*Scissors
1. Put the front end of the car on ramps or jackstands
2. Spray the O2 sensors with PB blaster (or other lubricant) to make removal easier; wait ten minutes.
3. Using the O2 sensor ratchet attachment, loosen the current O2 sensors that are installed in the “Y” portion of the Y-pipe
4. Trace the sensor harness up to the engine bay and unplug it. One will be close to the cabin, to the left of the spark plugs; the other will be clipped by the radiator, towards the front of the car
5. Cut the plastic things holding the harness; there will be multiple ones
6. Completely unscrew the O2 sensors
7. Plug in the new sensors to the now-empty connectors that the old sensors were attached to
8. Dangle the sensor from the engine bay to the underbody of the car, taking care to do it SLOWLY so you don’t damage the sensor
9. Put a little anti-seize on the threads of the sensors (if there isn’t any already)
10. Screw ’em in and you’re done.
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Downstream O2 sensor:
Necessary tools:
*12mm wrench
*OEM downstream O2 sensor
*Anti-seize
*PB Blaster (or WD40)
*Scissors
1. Put the rear end of the car on ramps or jackstands
2. Locate the downstream O2 sensor; it is in rear-half the catalytic converter, on the driver’s side (middle of the car is where you should be looking)
3. Spray the sensor with PB Blaster or WD40
4. Trace the harness to the underbody of the car
5. Pull on the harness until the rubber seal pops free
6. Disconnect the old sensor from the harness
7. Apply anti-seize to the new O2 sensor (if it doesn’t already have some); take care not to get the compound on the sensor head
8. Screw in the sensor
9. Connect the new sensor to the harness
10. Jam the excess wiring back into the hole and close it up with the rubber seal
11. Using one of the supplied zip ties, secure any slack wiring.
Article Provided By:Cullenj76