This guide provides step-by-step instructions on replacing the oxygen (O2) sensors on a 2002 Honda Prelude. This relatively simple task can improve performance, reduce emissions, and potentially improve fuel economy. New sensors can be purchased online for around $100.
Tools and new O2 sensors ready for installation.
Preparation and Initial Steps
Before starting, gather the necessary tools: a 10mm socket, a 22mm wrench, a heat gun (or a blowtorch or a 15-minute drive to heat the exhaust), gloves, two car lifts (recommended for safety), and about an hour of time.
Begin by warming up the car with a 15-minute drive. Then, safely lift the front right side of the car and remove the front right wheel for easier access. Although not strictly necessary, removing the wheel provides more room to work.
Locating and Removing the O2 Sensors
The O2 sensors are located near the catalytic converter on the exhaust manifold.
Bank 1 Sensor 1 (right) and Bank 1 Sensor 2 (left) locations.
The sensor closest to the engine is Bank 1 Sensor 1, while the one further down the exhaust is Bank 1 Sensor 2. Unplug the electrical connector for Bank 1 Sensor 1, located near the oil filter.
Unplugging the electrical connector for Bank 1 Sensor 1.
Use the 22mm wrench to remove Bank 1 Sensor 1 by turning it counter-clockwise. Next, unplug the electrical connector for Bank 1 Sensor 2, located closer to the front right wheel area.
Removing the Heat Shield and Bank 1 Sensor 2
To access Bank 1 Sensor 2, you’ll need to remove the heat shield above it. Use the 10mm socket to remove the two bolts securing the section of the heat shield covering the sensor. Complete removal of the heat shield isn’t necessary.
10mm bolts to remove for heat shield access to Bank 1 Sensor 2.
Unplugging Bank 1 Sensor 2 connector.
Once the heat shield section is loose, use the 22mm wrench to remove Bank 1 Sensor 2, again turning counter-clockwise.
Old O2 sensors after removal.
Installing the New O2 Sensors
Ensure the new sensors have anti-seize lubricant applied to the threads (often pre-applied). Install the new sensors by hand, then tighten them with the 22mm wrench to 33 ft-lbs of torque. This is roughly equivalent to tightening a spark plug. Ensure the electrical connectors are untwisted before plugging them in to avoid damage. Finally, reset the car’s computer by either disconnecting the radio fuse or disconnecting the battery for 30 seconds. Start the engine to verify the installation.
Results and Conclusion
After replacing the O2 sensors, you may notice improvements in engine smoothness, acceleration, reduced black smoke (especially when VTEC engages), and potentially better fuel economy. Driving for a few miles after the installation will allow the car’s computer to adjust to the new sensors.
