On a 2007 Honda Accord, the oxygen sensors are part of the exhaust system. The 2.4-liter inline-four uses two sensors—one upstream before the catalytic converter and one downstream after it. The 3.0-liter V6 uses four sensors—two upstream, one for each bank, and two downstream after each bank’s catalytic converter.
Exact mounting points can vary by market and trim level, but in general you’ll find the upstream sensors threaded into the exhaust pipes or manifolds before the catalytic converter, and the downstream sensors located after the catalytic converter along the exhaust stream. Access is typically from beneath the car or by removing some underbody shielding, and the sensor plugs connect to the engine’s wiring harness.
Engine options and sensor counts
The Accord offered two engines in 2007. The four-cylinder version uses two O2 sensors in total, while the V6 version uses four sensors — two upstream and two downstream — for each exhaust bank.
Four-cylinder engine (2 sensors)
For the 2.4L inline-four, the oxygen sensors are positioned as follows:
- Upstream (pre-cat) sensor: mounted in the exhaust manifold or the pipe just after the manifold, before the catalytic converter.
- Downstream (post-cat) sensor: mounted on the exhaust pipe after the catalytic converter.
These two sensors monitor exhaust gas composition before and after the catalytic converter and report data to the engine control module to regulate the air-fuel mixture and emissions.
V6 engine (4 sensors)
For the 3.0L V6, there are four oxygen sensors—two upstream and two downstream—one pair for each bank of cylinders:
- Upstream sensor for Bank 1: located near Bank 1’s exhaust manifold, before its catalytic converter.
- Downstream sensor for Bank 1: located after Bank 1’s catalytic converter in its downpipe.
- Upstream sensor for Bank 2: located near Bank 2’s exhaust manifold, before its catalytic converter.
- Downstream sensor for Bank 2: located after Bank 2’s catalytic converter in its downpipe.
These four sensors feed data to the ECU to optimize fuel delivery and monitor emissions across both exhaust banks.
Locating and accessing the sensors safely
To locate the sensors on your specific vehicle, start by referencing the owner's manual or a repair guide for your trim and VIN, since mounting can vary slightly by market. With the car safely raised and cooled, visually follow the exhaust pipes from the manifold area toward the Catalytic Converter; the sensors have threaded bodies with electrical connectors along the harness running toward the engine.
Summary
In the 2007 Honda Accord, oxygen sensor configuration depends on the engine. The 4-cylinder option uses two sensors (one upstream, one downstream), while the V6 option uses four sensors (two upstream, two downstream) placed along each bank’s exhaust path. Understanding their locations helps with diagnostics, replacement, and maintenance to keep the vehicle’s emissions and fuel system functioning properly.