Parts for your 2009 Honda Accord-Oxygen sensor

2009 Honda Accord Oxygen Sensor — What It Does and When to Replace It

Yes, the 2009 Honda Accord is fitted with oxygen sensors. Technical sources including the Honda Accord 2008–2012 Service Manual (Fuel and Emissions section), Honda’s OEM parts catalogues, and application guides from NTK/NGK and Denso confirm that this model uses an upstream air–fuel ratio (A/F) sensor and a downstream oxygen (O2) sensor on four-cylinder variants, and two upstream A/F sensors plus two downstream O2 sensors on V6 variants. These sensors are integral to the engine management and emissions systems, so they’re absolutely relevant on this model.

On the 2009 Accord, the upstream A/F sensor reads the oxygen content right as exhaust leaves the engine, letting the ECU fine-tune the air–fuel mix for smooth running, good economy, and lower emissions. The downstream O2 sensor sits after the catalytic converter to monitor how effectively the cat is cleaning up the exhaust. Together they help the car meet emissions standards, protect the catalyst, and keep petrol consumption in check.

Owners will typically notice the benefits of healthy sensors as steady idle, crisp throttle response, and consistent fuel economy. When they start to degrade, the check engine light may appear, fuel use can climb, and the car might feel a bit lazy or smell rich. Fault codes like P0134, P0135, P0138, P0141 or P0420 are common clues the system needs attention, and scan-tool fuel trims that drift high can also point to a lazy sensor.

While oxygen sensors aren’t a strict “every-service” item, they do wear out. It’s sensible to plan inspection or proactive replacement somewhere around 160,000–200,000 km, or earlier if there are fault codes or obvious symptoms. The four-cylinder typically has two sensors, the V6 has four, so parts and labour will vary by engine.

• Use quality OEM-grade sensors (NTK/NGK or Denso are common OE suppliers).
• Only use anti-seize if specified by the sensor manufacturer, many sensors come pre-coated.
• Use an O2-sensor socket, avoid twisting the wiring, and tighten to factory spec.
• Clear fault codes after replacement and complete a drive cycle so readiness monitors reset.
• If a sensor is contaminated (oil, coolant, silicone), fix the root cause or the new sensor may fail early.

For the 2009 Honda Accord, keeping the oxygen sensors in good nick is an easy win for smoother running, better fuel economy, and a happy catalytic converter.

Popular questions

How many oxygen sensors does a 2009 Honda Accord have?
Four-cylinder Accords usually have two sensors: one upstream A/F (Bank 1 Sensor 1) and one downstream O2 (Bank 1 Sensor 2). V6 models typically have four sensors: two upstream A/F sensors (one per bank) and two downstream O2 sensors to monitor each catalytic converter.

What are common symptoms of a failing oxygen sensor?
Expect a check engine light, increased fuel use, rough or wandering idle, hesitation on take-off, or a sulphur/“eggy” smell from the exhaust. Scan tools may show rich/lean codes or catalyst efficiency faults. If the Accord feels thirstier than usual, the O2/A/F sensors are a prime suspect.

When should the oxygen sensors be replaced on a 2009 Accord?
They’re not a fixed-interval service part, but many owners replace them around 160,000–200,000 km, or sooner if fault codes or symptoms appear. Replacement time ranges from about 30–90 minutes per sensor depending on access and corrosion. Always address any underlying issues that might have damaged the old sensor.