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Quick Answer: What This Kit Is

The 2pcs Upstream Air Fuel Ratio O2 Sensor Kit for the 2004–2008 Nissan Maxima 3.5L V6 replaces both pre-catalyst sensors in one purchase — Bank 1 Sensor 1 and Bank 2 Sensor 1. Fitment covers 2004, 2005, 2006, 2007 and 2008 Maximas with the 3.5L V6, naturally aspirated only.

Each unit is a planar zirconia wideband AFR sensor in a 4-wire heated configuration. It replaces Nissan OEM part number 22693-7Y000, cross-references 22693-7S000 and Denso 234-5060, and matches the NTK planar-type wideband series. Unlike a narrowband unit stuck in the 14.5:1–14.9:1 window, this element reads 10:1–20:1, so your ECU gets usable feedback across the whole map.

Fitment and Protocol Facts

• Compatibility: 2004–2008 Nissan Maxima 3.5L V6 (VQ35DE), naturally aspirated only
• Position: upstream, pre-catalytic converter — one sensor per bank
• Bank 1: firewall side, cylinders 1-3-5. Bank 2: radiator side, cylinders 2-4-6
• Cross-reference: Nissan 22693-7Y000, 22693-7S000 | Denso 234-5060 | NTK equivalent
• Protocol: ISO 15765-4 CAN-BUS, fully OBD II compatible — and yes to 2026 CAN-bus 3.0, since the VQ35DE ECU communicates over ISO 15765-4 and these sensors hold signal integrity across all CAN-bus diagnostic layers

Technical Specifications

All figures come straight from the 2026 technical review for this kit.

Against the single-sensor options: the OEM 22693-7Y000 runs 2.5–4.0 Ω heater resistance with light-off up to 12 seconds; the Denso 234-5060 runs 2.3–4.2 Ω with light-off ≤ 10 seconds and a standard protection layer. Both sell one sensor per box. The Koeep pair matches on type, lambda range and temperature rating, then adds the second matched unit.

Planar Zirconia Technology in Brief

One Ceramic Stack, Two Functions

The planar element fuses the sensing cell and the heater circuit into one multi-layer ceramic substrate with an integrated platinum heater trace. Older cup-shaped sensors separate those functions, which adds mass and slows warm-up. Planar construction is the dominant 2026 aftermarket standard — and the reason the ≤10-second light-off is possible.

Housing, Heat and Anti-Fouling Chemistry

The element sits in a 304L stainless steel housing with laser-welded hermetic seams, rated for continuous exhaust temperatures up to 1,050°C (1,922°F). A proprietary anti-fouling diffusion layer resists silicone and phosphorus poisoning — the leading cause of premature AFR sensor failure on high-mileage VQ35DE engines.

DTC Guide: Codes This Kit Clears

Under the 2026 CARB OBD readiness regulations effective October 1, 2025, any of these codes blocks a Smog Check. The kit covers the full VQ35DE upstream AFR matrix:

• P0130 / P0133 / P0135 — Bank 1 Sensor 1: circuit malfunction, slow response, heater circuit malfunction
• P0150 / P0153 / P0155 — Bank 2 Sensor 1: circuit malfunction, slow response, heater circuit malfunction
• P0031 / P0032 — Bank 1 Sensor 1 heater control circuit low / high. P0051 / P0052 — same fault on Bank 2 Sensor 1
• P0171 / P0174 — System Too Lean, Bank 1 / Bank 2, often triggered by a degraded upstream sensor providing false lean readings — so test the sensors before chasing vacuum leaks

Failure Symptoms to Check First

• Fuel economy drop: a 15–25% decrease in MPG is the most common early sign. The ECU defaults to open-loop rich fueling when sensor data is unreliable.
• Rough idle and hesitation: worst on cold starts, when a sluggish sensor fails during warm-up enrichment.
• Failed Smog Check: an incomplete oxygen sensor monitor means automatic rejection under the October 2025 rules.
• Live data anomalies: a healthy planar AFR sensor switches rapidly on a scan tool; a failing unit shows sluggish or flatlined response.
• Exhaust odor: unburned fuel smell points to rich running from faulty upstream feedback.

Replace Both Sensors, Not One

The VQ35DE ECU compares Bank 1 and Bank 2 AFR readings to calculate individual cylinder fuel trims. Pair an aged, slow sensor with a new one and the ECU can hold a persistent fuel trim asymmetry between banks.

The classic result: P0171 or P0174 on one bank only, a rough idle, and extra stress on the catalytic converters. Paired replacement is the recommended 2026 service protocol.

The Koeep 2-pack removes that variable with matched sensors and identical calibration curves — one box, both banks, done.

Scanner and Protocol Compatibility

Your Maxima communicates over ISO 15765-4 (CAN-BUS). SAE J1979-2 OBDonUDS is the 2026 forward-looking standard aimed at newer vehicles, and current OBD II scan tools stay backward-compatible with the VQ35DE implementation.

The sensors output an analog signal that the ECU digitizes and transmits over CAN, so there is no sensor-level conflict with 2026 diagnostic equipment. For the bank-by-bank walkthrough and live-data steps, read the 2026 Guide to diagnosis, replacement and performance.

Related Parts for Your Maxima

This generation wears more than O2 sensors. If the transmission acts up in the same service window, Koeep carries the 31935-8Y000 reference for 2004–2009 Altima, Maxima and Quest as a Trans Input Speed Sensor 2pcs set.

The same 31935-8Y000 part also appears as an Input Shaft Speed Sensor 2pcs for the Altima and Maxima — two pages, one reference, so you can match the part to your harness. If the fault traces to the electronics side instead, the Starters, Alternators & ECUs collection holds the full electrical catalog.

2026 Compliance and Market Outlook

The kit conforms to SAE J1979-2 diagnostic architecture requirements for emissions-related sensor data reporting. The anti-fouling diffusion layer meets ISO 15031-5 durability standards, and materials comply with 2026 EPA Tier 4 and CARB LEV IV aftermarket parts provisions.

Supply stays strong: the global automotive oxygen sensor market sits at $9.62 billion in 2026 (6.5% CAGR), with planar AFR sensors growing at 14.1%, and is projected to reach $12.36 billion by 2030. Garages and fleets can submit a request for quote for volume pricing.

FAQ: 2026 Diagnostic Questions