The 1998 Honda Accord uses two oxygen sensors in its exhaust system and, while they are in different parts of the exhaust, they serve similar functions. The oxygen sensor reads the percentage of oxygen in the exhaust and sends the information to the powertrain control module, which in turn adjusts the pulse width at the fuel injector to regulate the air/fuel mix coming out of the fuel injectors. If an oxygen sensor fails, the car can stall, idle roughly, or have reduced fuel economy.
Raise the front of your Accord with a jack, then position a set of jack stands under the front of the car. Lower the jack until the jack stands are supporting the weight of the car. Remove the jack from under the car.
Locate the oxygen sensors in the exhaust system. The first is in the head pipe, just in front of the mounting flange for the catalytic converter. The second is right behind the catalytic converter, and it is technically a catalytic monitor. The process is the same for replacing either one.
Locate the wiring harness connector where the pigtail from the oxygen sensor and the wiring harness from the car come together. Release the locking clip and separate the two halves of the connector.
Remove the oxygen sensor from the exhaust system using a oxygen sensor socket and ratchet. Turn the sensor counterclockwise until it is free of the exhaust pipe. Discard the old sensor.
Install a new oxygen sensor in place of the one you removed and tighten it to 33 pound-feet of torque with a torque wrench. Install the connector on the sensor's wiring pigtail into the connector on the car's wiring harness. Push the two connectors together until the locking tab engages.
Position the jack under the front of the Accord and lift the car off the jack stands. Remove the jack stands from under the car and lower the Accord.
