The oxygen sensors on the 2010 Honda Accord are located in the exhaust system: one upstream sensor sits before the catalytic converter and one downstream sensor sits after it on the 4-cylinder model; the V6 version adds a second bank, bringing the total to four sensors. This guide breaks down exact placements for both engines.
Engine configurations and sensor layouts
The 2010 Accord offered two engines: a 2.4L inline-4 and a 3.5L V6. The number and placement of O2 sensors depend on which engine you have. The following outlines the typical locations for each engine.
Four-cylinder (2.4L) engine
In the 4-cylinder Accord, there are two O2 sensors on the exhaust run: one upstream (before the catalytic converter) and one downstream (after the catalytic converter). They are mounted in the exhaust pipe near the cat and are connected to the engine wiring harness.
- Bank 1 Sensor 1 (upstream): threaded into the exhaust pipe between the exhaust manifold and the catalytic converter (usually on the passenger side of the engine bay).
- Bank 1 Sensor 2 (downstream): threaded into the exhaust pipe after the catalytic converter, along the pipe toward the rear of the vehicle.
Before listing the sensor locations, this brief guide clarifies which sensor is where on the 4-cylinder engine.
In short, for the 4-cylinder 2010 Accord, look for two sensors on the same exhaust run: one before and one after the catalytic converter.
V6 (3.5L) engine
The V6 model uses two exhaust banks. Each bank carries an upstream and a downstream sensor, yielding four sensors total. The layout mirrors the four-cylinder pattern but on both banks.
- Bank 1 Sensor 1 (upstream): on Bank 1’s exhaust pipe, before its catalytic converter.
- Bank 1 Sensor 2 (downstream): after Bank 1’s catalytic converter on that bank.
- Bank 2 Sensor 1 (upstream): on Bank 2’s exhaust pipe, before its catalytic converter.
- Bank 2 Sensor 2 (downstream): after Bank 2’s catalytic converter on that bank.
Before listing the sensor locations, this paragraph explains the four-sensor arrangement on the V6.
With the V6 configuration, expect four sensors total, aligned with each bank’s upstream and downstream positions.
Locating and safely handling O2 sensors
From a practical standpoint, technicians identify sensors by tracing the wiring harnesses from the engine toward the exhaust. Upstream sensors typically sit closer to the engine, near the manifold, while downstream sensors are after the catalytic converters. Always allow the exhaust system to cool before handling, disconnect the negative battery terminal, and use the appropriate socket to avoid damaging the sensors.
Quick tips for identification
Look for two sensors on each bank for the V6, and observe that the upstream sensor is located before the cat, while the downstream sensor is located after the cat. The connectors are color-coded in some models, but not reliably across all vehicles.
Summary
In the 2010 Honda Accord, the O2 sensor locations depend on the engine. The 4-cylinder version has two sensors—upstream and downstream—on a single exhaust run. The V6 version has four sensors—two on each bank, one upstream and one downstream per bank. If you’re diagnosing emissions codes or planning a replacement, verify the engine type and follow the wiring harnesses to identify each sensor, taking care with hot components and the exhaust system.