Front Lambda Oxygen O2 Sensor 03L906262P for Audi A1 A3 A4 A5 A6 A7 A8

If you're chasing a check engine light, a rough idle, or fuel economy that's quietly gotten worse, the front oxygen sensor is one of the first places to look. This listing is for a brand new, aftermarket Audi A4 A6 oxygen sensor — a 5-wire front (upstream) lambda sensor, OE part number 03L906262P, built to read correctly on a wide range of Audi and other Volkswagen Group vehicles. It's not used or reconditioned; it's a straightforward, correctly-wired replacement for a sensor that wears out on every car eventually.

Why the front sensor matters more than people think

There are usually two oxygen sensors per bank on these engines: one upstream (front, pre-catalytic converter) and one downstream (rear, post-cat). The rear sensor mostly just checks that the catalytic converter is doing its job. The front sensor is the one the ECU actually listens to for fuel trim — it measures oxygen content in the exhaust leaving the engine in real time and tells the ECU whether the mixture is running rich or lean, feedback the ECU uses constantly to adjust injector pulse width and keep combustion close to ideal.

When a front lambda sensor starts to drift or fail — usually from age, oil contamination, or a degraded sensing element — that feedback loop breaks down, the ECU falls back to a fixed map or compensates incorrectly, and that's when you notice it in how the car drives and what it costs to run.

Symptoms of a failing front O2 sensor

A tired or failing upstream sensor doesn't always announce itself with a dramatic failure. More often it shows up as a handful of smaller annoyances that add up:

• Check engine light on, often with fault codes pointing to O2 sensor circuit performance or fuel trim being out of range
• Noticeably worse fuel economy, since the ECU can't fine-tune the air/fuel mixture without accurate feedback
• Rough or uneven idle, hesitation on acceleration, or a slight surge at steady cruising speed
• A failed emissions or MOT-style test, since incorrect fuel trim skews tailpipe readings even if the catalytic converter itself is fine
• A faint sulfur or "rotten egg" smell from the exhaust in some cases, as the mixture runs rich

None of these are exclusive to a bad O2 sensor — a vacuum leak or a tired coil can look similar — but if you've got a check engine light with an oxygen sensor or fuel trim code stored, and the sensor is original or unknown-age, it's a cheap part to rule out first.

Specifications

• Type: Front (upstream) lambda / oxygen sensor
• Wiring: 5-wire connector
• Condition: Brand new, aftermarket (unbranded)
• Quantity: 1x sensor
• Primary OE reference: 03L906262P
• Also cross-references to: 03G906262A, 03G906262C, 03G906262D, 03G906262F, 03G906262H, 03G906262N, 03L906262, 03L906262B, 03L906262F, 03L906262J, 03L906262K, 03L906262S, 045906262, 057906262D, 057906262F, 059906262, 059906262B, 059906262F, 059906262H, 059906262J, 059906262K, 070906262B, 1K0998262AD, 8200406337, 8200230256, 8200351037, 8200616106, 8R0906262, 03C906262D, 0281004027, 0281004085, 0281004086, 0258017052, 0258017111, 0281004148

Always match the OE number against your existing sensor or your service documents before ordering — the same platform can carry more than one variant depending on engine and model year.

Audi A4, A6 and Other Audi Models This Oxygen Sensor Fits

This is a genuinely shared Volkswagen Group part, and it covers a long run of Audi models:

A1 (8X1, 8XK) 2.0 from 2011+; A1 Sportback (8XA, 8XF) 2.0 from 2011+; A3 (8P1) 1.9/2.0, 2003–2012; A3 Cabriolet (8P7) 1.9/2.0, 2008–2013; A3 Sportback (8PA) 1.9/2.0, 2004–2013; A4 (8K2, B8) 2.0/2.7/3.0, 2007–2015; A4 Allroad (8KH, B8) 2.0/3.0 quattro, 2009–2016; A4 Avant (8K5, B8) 2.0/2.7/3.0, 2008–2015; A5 (8T3) 2.0/2.7/3.0, 2007–2017; A5 Cabriolet (8F7) 2.0/2.7/3.0, 2009–2017; A5 Sportback (8TA) 2.0/2.7/3.0, 2009–2017; A6 (4F2, C6) 2.0/2.7/3.0, 2004–2019; A6 Allroad (4FH/C6, 4GH/4GJ) 2.7/3.0, 2006–2014; A6 Avant (4F5/C6) 2.7/3.0, 2005–2011; A6 Avant (4G5/C7/4GD) 2.0/3.0, 2011–2019; A7 Sportback (4GA) 3.0, 2010–2018; A8 (4H2/4H8/4HC/4HL) 3.0/4.2 quattro, 2009–2018; and TT (8J3)/TT Roadster (8J9) 2.0 quattro, 2008–2014.

If you're working on an Audi A4 or A6 from the B8/C6/C7 era, this is one of the most common front sensor part numbers you'll come across, since those platforms were built in huge numbers with this same emissions setup.

Also fits the wider Volkswagen Group lineup

Because Audi, Volkswagen, SEAT, and Skoda share engines and emissions hardware across the same corporate platforms, this sensor and its OE numbers turn up well beyond Audi badges. It also fits Porsche Cayenne (92A) 3.0 Diesel (2010–2019) and Macan (95B) 3.0S Diesel (2014–2019); SEAT Alhambra, Altea, Altea XL, Cordoba, Exeo, Ibiza III/IV, Leon, and Toledo III; Skoda Fabia II/Combi, Octavia II/Combi, Roomster/Praktik, Superb II/Kombi, and Yeti; and Volkswagen Amarok, Beetle/Cabriolet, Caddy III/IV, Crafter, EOS, Golf Plus/V/V Variant/VI/VI Cabriolet/VI Variant, Jetta III/IV, Multivan V/VI, Passat/Alltrack/CC/Variant, Phaeton, Polo, Scirocco, Sharan, Tiguan, Touareg, Touran, and Transporter V/VI. Match the OE number against the list above to confirm fitment — with a shared-platform part like this, the number is more reliable than the model name alone.

To understand more about what this sensor actually measures and why it matters for emissions control, the Wikipedia article on oxygen sensors is a solid, plain-language technical reference.

Fitting notes and what's in the box

You're getting one brand new, unbranded aftermarket front oxygen sensor, 5-wire, ready to install. As with any O2 sensor swap, a light coat of anti-seize on the threads (keeping it off the tip and slots) makes future removal easier, and the connector should click in fully so the ECU gets a clean signal. If you clear codes after fitting, give the car a proper drive cycle first — fuel trim codes often need a few warm-up cycles to fully reset.

We stock this as part of our Electrical Parts range and our Exhaust & Emissions collection, alongside other sensors and emissions components for Audi and Volkswagen Group vehicles — see our dedicated Audi parts collection and Volkswagen parts collection if you're sourcing more than one item for the same car.

Questions before you order?

Cross-referencing an O2 sensor against your chassis code and engine can be fiddly, and we'd rather you check than guess. If you're not sure this is right for your car, get in touch with our team before ordering, or check our frequently asked questions for common fitment queries. Once ordered, follow it through our order tracking page, and our shipping information page covers dispatch and delivery. Every sensor we sell is backed by our warranty policy. If you need a part that isn't listed yet, our request a part page is the quickest way to ask us to source it.