The oxygen sensors on a 2010 Honda Accord are located along the exhaust system: the four-cylinder model uses two sensors (one upstream before the catalytic converter and one downstream after it), while the V6 version typically uses four sensors (two upstream, one downstream for each bank). They are installed along the exhaust pipes under the car and are accessible from underneath during inspection or replacement.
Engine configurations and sensor counts
Four-cylinder 2.4L
The following outlines the location for the two oxygen sensors on the four-cylinder engine. This setup includes one upstream sensor before the catalytic converter and one downstream sensor after the catalytic converter.
- Upstream O2 sensor (pre-cat): threaded into the exhaust pipe just downstream from the exhaust manifold, ahead of the catalytic converter. It sits closest to the engine.
- Downstream O2 sensor (post-cat): threaded into the exhaust pipe after the catalytic converter; positioned along the pipe, typically toward the middle or rear undercarriage.
In the four-cylinder version, both sensors are used by the engine control system to regulate air-fuel mixture and monitor exhaust composition.
V6 3.5L
The V6 configuration uses four sensors in most setups: one upstream sensor on each bank (before its catalytic converter) and one downstream sensor on each bank (after its catalytic converter).
- Upstream Sensor Bank 1 (pre-cat): located on the Bank 1 exhaust manifold, just before its catalytic converter.
- Upstream Sensor Bank 2 (pre-cat): located on the Bank 2 exhaust manifold, just before its catalytic converter.
- Downstream Sensor Bank 1 (post-cat): located after the Bank 1 catalytic converter along that bank’s exhaust pipe.
- Downstream Sensor Bank 2 (post-cat): located after the Bank 2 catalytic converter along that bank’s exhaust pipe.
These four sensors work together to provide real-time feedback to the engine computer, helping to optimize emissions and fuel efficiency across varying conditions.
Practical notes for locating and safety
When locating or replacing oxygen sensors, ensure the vehicle is securely parked, the engine is cool, and you have the proper tools (a dedicated O2 sensor socket and penetrating oil). Be mindful of hot exhaust components and the sensors’ exposed electrical connectors, which can be sensitive to moisture and corrosion.
If you’re unsure about which sensors your specific trim uses, consult the owner’s manual or a service guide for your exact VIN, as there can be minor variations by market or model sub-variant.
Summary
For the 2010 Honda Accord, four-cylinder models have two O2 sensors—upstream and downstream—located along the exhaust pipe near the catalytic converter. The V6 models typically employ four sensors—two upstream, one per bank, and two downstream after each catalytic converter. Access is from underneath the vehicle, along the exhaust system, with the upstream sensors closer to the engine and the downstream sensors farther back.