Maxfavor Oxygen Sensor Pair for Nissan Altima & Maxima 2008-2010 — Upstream 234-9038 & Downstream 234-4381, Direct-Fit Durable Rep

This Maxfavor two-piece oxygen sensor set (234-9038 upstream + 234-4381 downstream) replaces the factory O2 sensors on 2008–2010 Nissan Altima and Maxima 2.5L and 3.5L engines.

These Maxfavor sensors are direct-replacement oxygen sensors engineered to match OE fit and function for the specified Nissan models and years. Built from durable materials and designed for a straightforward swap, the pair includes one upstream (pre-catalyst) sensor and one downstream (post-catalyst) sensor so you can address both diagnostic and performance needs at once.

How will replacing both upstream and downstream sensors affect my car?

Swapping in new upstream and downstream sensors restores the engine control module's ability to read exhaust oxygen levels accurately. That helps the ECU better balance air/fuel mixtures and monitor catalytic converter performance without making performance promises.

• Includes 234-9038 upstream and 234-4381 downstream sensors for correct placement.
• Direct-fit design reduces the need for modification or splicing.
• Durable construction intended for long-term use in exhaust environments.

What should I check before buying these Maxfavor sensors?

Verify vehicle year, make, engine size, and existing connector type to be certain of compatibility. Compare the pictured sensors and connectors with the parts on your vehicle to confirm identical thread size, wiring, and plug orientation.

• Compatible with 2008–2010 Nissan Altima and Maxima 2.5L and 3.5L engines.
• Confirm sensor part numbers (234-9038 upstream, 234-4381 downstream) match your replacement needs.
• Inspect connector shape and thread pitch against your original sensors before installation.

How difficult is installation and what tools are needed?

Installation is a common DIY job if you have basic hand tools and a suitable oxygen sensor socket or wrench. The typical steps are removal of the old sensor, cleaning the threaded port, comparing parts, installing the new sensor hand-tight then torqued to spec, and reconnecting the electrical plug.

• Required tools: oxygen sensor socket, ratchet, anti-seize (if not pre-applied), and possibly penetrating oil.
• Recommended steps: locate sensor, remove old unit, clean threads, install new sensor, secure wiring clear of heat sources.
• If codes remain after installation, clear diagnostic trouble codes with an OBD-II scanner.

What warranty and post-purchase support does Maxfavor provide?

Maxfavor backs the sensors with a one-year unlimited-miles warranty and accepts returns if the parts don’t fit. Customer support is available by email for fitment questions or replacement assistance.

• 1-Year unlimited miles warranty from Maxfavor on manufacturing defects.
• Return accepted if the sensors do not match vehicle fitment—keep the item clean and packaged.
• Seller response typically within 24 hours for fitment or installation inquiries.

Who is this for: This Maxfavor 2-piece oxygen sensor set is for Nissan owners, independent mechanics, and DIY enthusiasts who need a reliable, direct-replacement upstream and downstream O2 sensor solution for 2008–2010 Altima and Maxima 2.5L and 3.5L engines. Choose this pair if you want matching sensors designed for correct placement, straightforward installation, and manufacturer support without altering vehicle wiring or exhaust hardware.