How to Replace the O2 Sensor on a Maxima

Oxygen sensors tend to seize to the exhaust tubes from constant heating and cooling of the exhaust system. It is a good idea to apply penetrating oil to the sensors threads one or two hours before attempting to remove them. It will make your job much easier. Letting the engine reach operating temperature also helps to remove the sensors. However, you might want to wear working gloves and be very careful to avoid skin burns.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Penetrating oil
• Floor jack and 2 jack stands
• Ratchet
• Oxygen sensor wrench
• High-temperature nickel anti-seize compound

1. Park your car in a safe place with a level surface. Open the hood and disconnect the black, negative battery cable.

2. Raise the front of your car using a floor jack and 2 jack stands.

3. Locate the sensors by following the front exhaust pipes connected to the exhaust manifolds on both sides of the engine. The sensors are threaded into the exhaust pipes just before the catalytic converter. They have a cylindrical body and the size of a spark plug.

4. Unplug the sensors electrical connectors by pressing the lock tab on the connectors and pulling the connector from the wiring harness.

5. Unscrew the sensors using a ratchet and an oxygen sensor wrench. Remove the sensors from the vehicle.

6. Apply a light coat of high-temperature nickel anti-seize compound to the sensors threads, making sure not to get compound on the tip of the sensors. Start the sensors by hand to avoid damage to the threads; then tighten the sensors being careful not to over tighten.

7. Plug the sensors electrical connectors, lower the vehicle and connect the black, negative battery cable.

Tips & Warnings

• Consult your owner's manual or vehicle service manual to identify or locate components. You can buy one at most auto parts stores or consult one for free at most public libraries.
• The engine may reach an operating temperature in a matter of minutes with the exhaust system reaching very high temperatures. Be careful when working on any part of this system to avoid skin burns and other serious injuries.

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