Is this sensor upstream or downstream?

It is the downstream sensor for most listed applications, such as the Trailblazer, Envoy, Malibu, Equinox and Colorado. A few listings, like the Express 1500 and Savana 2500/3500, are upstream, so check your vehicle and position before ordering.

Will it fix a P0420 code?

Only if the rear sensor is the cause. P0420 often means a failing catalytic converter, and a new downstream sensor will not fix that. Scan the sensor's voltage before replacing it.

Is it worth it over an OEM sensor?

At $19.99 it is a low-cost option for an older vehicle. OEM sensors cost several times more and usually last longer, so it is a reasonable budget choice but not a long-term match for a dealer part.

Does it come with a connector and threads ready to install?

It is sold as a direct-fit replacement with the correct connector for the listed applications. You will still need a sensor socket and may need penetrating oil on a rusted bung.

When is the price lowest?

The current $19.99 at Walmart as of November 6, 2026 is already near the bottom of its recent range. Five stores list it new, so compare total cost with shipping before buying.

One oxygen sensor. No socket or anti-seize is included unless the listing says so.

Where can I buy the A-premium Downstream Center O2 Oxygen Sensor?

5 stores we checked sell it, including Walmart, A-Premium, CarParts.com, eBay, Amazon.

A-premium Downstream Center O2 Oxygen Sensor

Best price now

$19.99at WalmartObserved at 4:58 AM

Compared across 5 stores. Prices are checked against each store and labelled with when.

Visit Walmart

A-premium Downstream Center O2 Oxygen Sensor

Best price now

$19.99at WalmartObserved at 4:58 AM

Compared across 5 stores. Prices are checked against each store and labelled with when.

Visit Walmart

Ask our agent about this product

It checks today's price at every store, compares the alternatives and answers in about a minute.

Our take on the A-premium Downstream Center O2 Oxygen Sensor

A-premium's downstream oxygen sensor is a direct-fit replacement for the post-catalyst sensor on a long list of GM, Isuzu, Hummer and Saab vehicles, mostly 2007-2014 four-, five- and six-cylinder models. It is a budget part that claims to meet or exceed OEM specs and carries a one-year quality guarantee. At $19.99 at Walmart as of November 6, 2026, it sits at the low end of its recent range, well under what a dealer-brand sensor typically costs.

Best forOwners of 2007-2014 GM, Isuzu or Saab models with a downstream sensor codeBudget repairs on older high-mileage vehiclesDIYers who want a cheap plug-in replacementFixing a P0137/P0138 or P0420 code caused by a lazy rear sensor

Pros

Low price: $19.99 at Walmart as of November 6, 2026
Covers a wide range of GM and Isuzu applications
Claims to meet or exceed OEM specifications
One-year quality guarantee
Downstream fitment listed for most applications, so the connector and thread match

Cons

Budget brand with little independent test data
Fitment list is long and easy to misread; upstream and downstream versions are mixed in
No heater or response-time specs published
Durability on high-mileage engines is unproven
Some applications need the upstream version, which this listing is not

A-premium Downstream Center O2 Oxygen Sensor prices at every store

WalmartNew
In stockSold by A-Premium
$19.99Free shippingObserved at 4:58 AM
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A-PremiumNew
In stock
$22.99Free shippingObserved at 4:58 AM
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CarParts.comNew
In stock
$27.99Free shippingObserved at 4:58 AM
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eBayNew
Availability unknownSold by a-premium-us (99.9% positive, 213,100 ratings)Returns: Set by the eBay seller; the eBay Money Back Guarantee covers an item that doesn't arrive or isn't as described.
$22.45Free shippingVerified
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AmazonNew
Availability unknown
As an Amazon Associate, Deal.ai earns from qualifying purchases.
$31.99Observed at 4:58 AM
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A-premium Downstream Center O2 Oxygen Sensor price history

Lowest price we've seen: $19.99 on Nov 6 at Walmart. Tracked across 4 stores since Nov 6.

About the A-premium Downstream Center O2 Oxygen Sensor

A-premium oxygen sensors are an ideal choice to replace your broken oxygen sensors. All oxygen sensors meet or exceed OEM specifications. Due to high manufacturing standard, it will come with one year quality guarantee. Compatible with following Buick Models: Rainier 2007 L6 4.2L, Enclave 2008 V6 3.6L, Lacrosse 2010 I4 2.4L Downstream Lucerne 2009-2011 V6 3.9L Downstream Compatible with following Chevrolet Models: Express 1500/Savana 1500 2014 V6 4.3L/V8 5.3L Upstream Express 2500/Express 3500 2014 V8 4.8L/V8 6.0L Upstream Trailblazer 2007-2009 L6 4.2L Downstream Colorado 2007-2012 I4 2.9L/L5 3.7L Downstream Malibu 2008-2012 I4 2.4L Downstream Equinox 2010-2014 I4 2.4L Downstream Captiva Sport 2012-2014 I4 2.4L Downstream Compatible with following GMC Models: Savana 2500/Savana 3500 2014 V8 4.8L/V8 6.0L Upstream Acadia 2007-2008 V6 3.6L Downstream Envoy 2007-2009 L6 4.2L Downstream Canyon 2007-2012 I4 2.9L/L5 3.7L Downstream Savana 3500 2008-2010 V8 6.0L Upstream Terrain 2010-2014 I4 2.4L Downstream Compatible with following Hummer Models: H3 2007-2010 L5 3.7L Downstream H3T 2009-2010 L5 3.7L Downstream Compatible with following Isuzu Models: Ascender 2007-2008 L6 4.2L Downstream I-290 2007-2008 I4 2.9L, I-370 L5 3.7L 2007-2008 Downstream Compatible with following Pontiac Models: Solstice 2008-2009 I4 2.4L Downstream G6 2008-2010 I4 2.4L Downstream Compatible with following Saab Models: 9-7X 2007-2009 L6 4.2L Downstream Compatible with following Saturn Models: Outlook 2007-2008 V6 3.6L Downstream Vue 2008-2010 I4 2.4L/V6 3.6L Downstream OEM Number: 12599204, 12604538, 12617907, 12597947, 12618010, 12618012, 250-24708 Location: Upstream or Downstream as per Application Quantity Sold: One Piece

Questions and answers

Is this sensor upstream or downstream?: It is the downstream sensor for most listed applications, such as the Trailblazer, Envoy, Malibu, Equinox and Colorado. A few listings, like the Express 1500 and Savana 2500/3500, are upstream, so check your vehicle and position before ordering.
Will it fix a P0420 code?: Only if the rear sensor is the cause. P0420 often means a failing catalytic converter, and a new downstream sensor will not fix that. Scan the sensor's voltage before replacing it.
Is it worth it over an OEM sensor?: At $19.99 it is a low-cost option for an older vehicle. OEM sensors cost several times more and usually last longer, so it is a reasonable budget choice but not a long-term match for a dealer part.
Does it come with a connector and threads ready to install?: It is sold as a direct-fit replacement with the correct connector for the listed applications. You will still need a sensor socket and may need penetrating oil on a rusted bung.
When is the price lowest?: The current $19.99 at Walmart as of November 6, 2026 is already near the bottom of its recent range. Five stores list it new, so compare total cost with shipping before buying.
What is in the box?: One oxygen sensor. No socket or anti-seize is included unless the listing says so.
Where is the A-premium Downstream Center O2 Oxygen Sensor cheapest?: At Walmart, for $19.99, as of our latest check.
Where can I buy the A-premium Downstream Center O2 Oxygen Sensor?: 5 stores we checked sell it, including Walmart, A-Premium, CarParts.com, eBay, Amazon.