Parts for your 2008 Nissan Maxima-Oxygen sensor

2008 Nissan Maxima oxygen sensor

The 2008 Nissan Maxima absolutely uses oxygen-sensing hardware. Per the Nissan Factory Service Manual (EC section: Air-Fuel Ratio Sensor and Heated Oxygen Sensor), the VQ35DE V6 runs two upstream air–fuel ratio (A/F) sensors and two downstream heated oxygen sensors (HO2S). Nissan’s parts catalog for the 2008 Maxima lists four sensors, and OBD‑II/ADR emissions requirements for petrol engines rely on these sensors for closed-loop fueling and catalyst monitoring. So, yes—oxygen sensors are fitted and very relevant to this model.

On this Maxima, the upstream A/F sensors (Bank 1 Sensor 1 and Bank 2 Sensor 1) sit in the exhaust manifolds and fine-tune the fuel mix for smooth running and good economy. The downstream HO2S (Bank 1 Sensor 2 and Bank 2 Sensor 2) live after the manifold cats to keep an eye on catalytic converter efficiency. Together, they help the ECU optimise fuel trims, cut emissions, improve throttle response, and avoid that thirsty, sooty feel.

As part of regular servicing, it’s smart to plan inspection and potential replacement around 160,000 km or when data and fault codes suggest ageing. Go for OE-quality (often Denso or NTK) and match the exact bank/sensor position—getting Bank 1 vs Bank 2 wrong is a common workshop hiccup.

• Typical symptoms of a tired sensor: higher fuel use, lazy throttle, rough idle, failed WOF/emissions, and a CEL with codes like P2A00/P2A03 (A/F sensor), P0138/P0158 or heater circuit faults (P0031–P0051). P0420/P0430 may be a cat issue, but a sluggish sensor can mislead diagnosis.

Replacement tips under the bonnet and from underneath:

1. Warm the exhaust slightly, then use a proper O2 sensor socket and penetrant. Don’t twist the loom.
2. Most new sensors come pre-coated, skip extra anti-seize unless specified. Tighten to manufacturer torque (snug, not gorilla tight).
3. Inspect connectors and heat shielding, brittle plugs and melted loom are common culprits.
4. Clear codes, reset fuel trims if needed, and complete a drive cycle so the ECU relearns.

Good preventative care: fix any exhaust leaks ahead of the sensors, keep the air filter and spark plugs fresh, and use quality petrol. That keeps the A/F and O2 sensors clean, the cats happy, and the Maxima humming along nicely.

Popular questions about 2008 Nissan Maxima oxygen sensors

How many oxygen sensors does a 2008 Maxima have?
It has four in total: two upstream air–fuel ratio sensors (one per bank) and two downstream heated oxygen sensors (one per bank) after the catalytic converters. That layout lets the ECU control mixture and verify catalyst performance.

Which side is Bank 1 on a 2008 Maxima?
On the transverse VQ35DE, Bank 1 is the rear (firewall side) bank containing cylinder 1. Sensor 1 is the upstream sensor in the manifold, Sensor 2 is the downstream sensor after the cat. Access to Bank 1 Sensor 1 can be tighter from the top, the fronts are usually easier from underneath.

Do I need to reprogram the ECU after replacing an oxygen sensor?
No reprogramming is typically required. Clear any codes, reset fuel trims if desired, and complete a normal drive cycle so closed-loop control and catalyst monitors can pass. If trims remain off, recheck for exhaust leaks or wiring issues.