The oxygen sensors in a 2008 Honda Accord are located in the exhaust system, with one sensor before the catalytic converter and another after it on the four-cylinder models. The V6 version uses a total of four sensors—two upstream (before each catalytic converter) and two downstream (after each catalytic converter). This placement allows the engine computer to monitor and adjust fuel mixture for emissions and efficiency.
Four-cylinder 2.4L engines
For the four‑cylinder 2008 Accord, expect two O2 sensors: one upstream and one downstream relative to the catalytic converter.
Before the list: here are the typical locations you’ll encounter on the four‑cylinder model.
- Upstream O2 sensor (before the catalytic converter): threaded into the exhaust pipe just after the exhaust manifold, usually on the passenger side of the engine bay and accessible from above.
- Downstream O2 sensor (after the catalytic converter): screwed into the exhaust pipe downstream of the cat, commonly along the mid‑section under the vehicle where the cat connects to the rest of the exhaust.
Concluding: these two sensors monitor exhaust gas before and after the catalytic converter to help regulate fuel delivery and monitor catalytic performance.
V6 engine (3.0L) configurations
The V6 version uses four O2 sensors because there are two banks and typically two catalytic converters—one upstream and one downstream for each bank.
Before the list: the four sensors on the V6 are positioned to monitor both banks of the exhaust system.
- Upstream sensor for Bank 1 (before Cat 1): located in the exhaust path on Bank 1, near the corresponding exhaust manifold before its catalytic converter.
- Upstream sensor for Bank 2 (before Cat 2): located in the exhaust path on Bank 2, near its exhaust manifold before the second catalytic converter.
- Downstream sensor for Bank 1 (after Cat 1): located after the first catalytic converter on Bank 1’s exhaust path.
- Downstream sensor for Bank 2 (after Cat 2): located after the second catalytic converter on Bank 2’s exhaust path.
Concluding: the four-sensor setup provides separate monitoring for each bank’s catalytic converter, aiding emissions control and engine management.
Maintenance and troubleshooting considerations
When servicing or replacing oxygen sensors, consult your owner’s manual or a service manual for the exact sensor part numbers and torque specifications. Use the correct oxygen sensor socket and apply anti-seize compound where recommended. If the check engine light is on and you’re diagnosing O2 sensor codes (for example P013x or P014x variants on Hondas), verify wiring, connectors, and the health of the catalytic converters in addition to the sensors themselves.
Summary
In summary, the 2008 Honda Accord has two O2 sensors on the four-cylinder model—one upstream, one downstream—located near the exhaust manifold and after the catalytic converter. The V6 model uses four sensors—two upstream and two downstream—distributed to monitor each bank’s catalytic converter. Knowing these locations can help with inspection, diagnostics, and replacement if faults arise.