Parts for your 2009 Honda Stream-Oxygen sensor

2009 Honda Stream oxygen sensor — what it does and when to replace it

On the 2009 Honda Stream (RN6–RN9 series, 1.8 R18A and 2.0 R20A petrol i‑VTEC), oxygen sensing is absolutely used and relevant. Honda’s factory service information for the RN6–RN9 PGM‑FI system details a primary Air/Fuel Ratio (A/F) sensor in the exhaust manifold and a secondary heated oxygen sensor (HO2S) after the catalytic converter. Honda’s electronic parts catalogues for these engines list both sensors as serviceable components, and 2009 OBD‑II/EOBD compliance requires upstream and downstream oxygen sensing to control fuelling and monitor catalyst efficiency. That all confirms the 2009 Honda Stream is fitted with oxygen sensors.

On this model, the primary A/F sensor continuously feeds back how rich or lean the mixture is so the ECU can trim fuel on the fly. The secondary HO2S sits after the cat and checks the catalyst is doing its job. Together, they help the Stream run smoothly, use less fuel, and keep emissions in check. If they age or get contaminated, drivers may notice higher fuel use, a rough idle, flat spots under load, or the check engine light with codes like P0134, P0135, P0138 or P0420.

Oxygen sensors aren’t a regular “every service” replacement on the Stream, but many workshops treat them as wear items around 160,000 km or sooner if symptoms or fault codes appear. As part of routine servicing, a tech should scan live data for the A/F sensor (current/λ) and secondary O2 (voltage switching), check for exhaust leaks, and verify the catalyst monitor runs to completion. If replacement’s needed, using OEM‑grade Denso or NTK parts is the safest bet.

• Always confirm the right sensor: the upstream A/F sensor is different to the downstream HO2S.
• Soak the threads on a cold exhaust, avoid twisting the harness, torque to manufacturer spec.
• Most new sensors come pre‑coated, don’t add copper anti‑seize unless the maker specifies it.
• Clear codes and perform a road test so the ECU relearns trims and completes OBD monitors.

For NZ and Australian owners (including JDM imports), the servicing approach is the same. Keeping the Stream’s oxygen sensors healthy helps it pull cleanly through the revs, saves a few bucks at the bowser, and keeps the WOF/rego inspector happy on emissions.

Popular questions

Where are the oxygen sensors on a 2009 Honda Stream?
There are two. The primary A/F sensor is screwed into the exhaust manifold close to the engine. The secondary HO2S is further back, mounted after the catalytic converter under the car. Access to the upstream sensor is from the engine bay, the downstream one is usually reached from underneath on stands or a hoist.

What are common signs the Stream’s O2 sensor is failing?
Tell‑tales include the check engine light, worse fuel economy, a lumpy idle, hesitation on take‑off, or a strong exhaust smell. Scan tools may show lazy or stuck readings from the secondary O2, or unstable λ from the A/F sensor. If a P0420 appears, rule out exhaust leaks and ageing sensors before condemning the cat.

Does a new oxygen sensor need programming?
No special coding is required on the 2009 Stream. Fit the correct sensor, check for exhaust leaks, clear any fault codes, and let the ECU relearn fuel trims with a decent road drive. Some workshops will perform an idle relearn and ensure all OBD monitors complete to confirm a good fix.