O2 Oxygen Sensor Upstream Downstream for Nissan Sentra (2003-2006) 1.8L

Direct-Fit O2 Sensor Kit for 2003-2006 Nissan Sentra (B15)

What it Does: This upstream and downstream oxygen sensor kit monitors exhaust oxygen on the 2003-2006 Nissan Sentra B15 1.8L QG18DE to regulate fuel trim and catalyst efficiency.

The Stock Nissan Sentra O2 Sensor Failure

Over high-mileage thermal cycles, factory sensing elements and heater circuits on the B15 Sentra QG18DE 1.8L fail from carbon fouling, oil ash, and thermal shock. When the upstream sensor slows or opens, the ECM enters rich open-loop fueling and sets codes like P0130, P0135, or P1273. Simultaneously, a fatigued downstream sensor fails to track catalyst oxygen storage, triggering P0136 or P0420.

Common Symptoms of a Failing OEM Oxygen Sensor

• Fault Codes & CEL: Stored P0130, P0135, P0141, or P0420 DTCs from slow switching or heater failures.
• Rich Fueling: Sluggish upstream feedback causes heavy fuel consumption, black soot, and fouled plugs.
• Drivability & Emissions: Unstable closed-loop control causes rough idle, hesitation, and failed tailpipe testing.

The Direct-Fit O2 Sensor Solution

Engineered to match OEM specs for 22693-CD700 and 22693-8U300, this matched pair restores rapid closed-loop feedback across exhaust manifold and post-catalyst bungs. Each sensor uses a laser-welded stainless housing, PTFE breather filter, and zirconia ceramic element built to withstand exhaust moisture and heat. Factory connectors plug straight into the QG18DE harness without splicing. Replacing 234-5061 and 234-4835 together ensures balanced voltage signaling.

What's Included

• 1 Upstream Oxygen Sensor (234-5061)
• 1 Downstream Oxygen Sensor (234-4835)

Technical Specifications

Compatibility

• 2003-2006 Nissan Sentra 1.8L

Frequently Asked Questions & Fitment Warnings

Does this fit the B15 Sentra?

Yes. Direct fit for the 2003-2006 Nissan Sentra QG18DE 1.8L. Excludes 2.5L QR25DE (SE-R / Spec V) models; confirm engine before ordering.

Will this clear P0130, P0135, or P0420 codes?

Yes, if sensor-related. New 234-5061 and 234-4835 sensors resolve heater and slow-response codes after clearing DTCs, though persistent P0420 may indicate a worn catalyst.

Are factory connectors pre-installed for plug-and-play fitment?

Yes. Both sensors feature OEM-style plugs; apply anti-seize sparingly to threads only and torque to spec.

The Nissan Precision Standard

Built for reliable fuel metering on daily-driven B15 platforms, this matched sensor kit restores factory economy and emissions compliance. Accurate voltage switching keeps your QG18DE running clean and CEL-free.