Guide to Oxygen Sensors for the 2015-2019 GMC Sierra 1500
Understand, diagnose, and choose the right replacement oxygen sensor to keep your Sierra's engine running efficiently.
- Your 2015-2019 Sierra has four O2 sensors; two upstream for fuel control and two downstream for catalyst monitoring.
- A bad sensor will trigger the Check Engine Light and hurt your fuel economy; ignoring it can damage your catalytic converter.
- ACDelco is the OEM brand, while NGK/NTK and Denso are highly regarded OEM-quality alternatives that are often recommended in owner forums.
- Always identify the correct sensor location (e.g., Bank 1, Sensor 2) before purchasing, as they are not interchangeable.
Understanding Oxygen Sensor Failure in Your Sierra
Oxygen sensors operate in a harsh environment of extreme heat and corrosive exhaust gases, meaning they eventually wear out. When a sensor fails, it can no longer send accurate information to your truck's computer. This often leads to a Check Engine Light, poor engine performance, and increased fuel consumption. Ignoring a failing upstream sensor can even lead to costly damage to your catalytic converters over time.
Key Failure Symptoms
The most common sign of a bad O2 sensor is a Check Engine Light. Other symptoms include noticeably worse gas mileage, a rough idle, hesitation during acceleration, and potentially a sulfur or "rotten egg" smell from the exhaust, which indicates a problem with the fuel mixture that could be damaging the catalytic converter.
🎬 Watch: Common symptoms of a failing oxygen sensorChoosing the Right Aftermarket Oxygen Sensor
When replacing an O2 sensor, you have several quality brands to choose from. It is crucial to select the correct sensor for the specific location (e.g., Bank 1 Sensor 1) as upstream and downstream sensors are not interchangeable.
- ACDelco: As the Original Equipment (OE) supplier for General Motors, ACDelco is the benchmark for fit and performance. Choosing ACDelco guarantees a part that is identical to the one your truck was built with.
- Denso & NGK/NTK: These brands are major OEM suppliers for many Japanese and domestic automakers and are widely considered to be of equal quality to OE parts. Forum discussions often reveal that ACDelco sensors are sometimes manufactured by NGK or Denso, making these excellent and often more affordable alternatives.
- Bosch: A pioneer in oxygen sensor technology, Bosch offers advanced wideband sensors. However, some vehicle owners in forums report mixed experiences with Bosch sensors on GM trucks, with a preference often given to NGK/NTK or Denso for this specific application.
- Walker Products: A well-known aftermarket brand that offers a more budget-friendly option. While they meet the required specifications, they may not have the same longevity or exact calibration as the premium OEM-equivalent brands.
| Brand Tier | Example Brands | Estimated Price (per sensor) |
|---|---|---|
| OEM | ACDelco GM Genuine | $75 - $195 |
| Premium Aftermarket | Denso, NGK/NTK, Bosch | $60 - $120 |
| Standard Aftermarket | Walker Products, TRQ | $51 - $90 |
Known Issues, Recalls, and Service Bulletins
As of early 2026, there are no specific NHTSA recalls for oxygen sensor failure on the 2015-2019 GMC Sierra 1500. However, in June 2014, General Motors issued a Preliminary Information bulletin (PIE0303) for the 2014 model year (which is mechanically similar) regarding the Check Engine Light illuminating with O2 sensor diagnostic trouble codes. This bulletin was for information gathering and did not constitute a recall. Before replacing a sensor, it's also wise to check the related fuses (in the main engine fuse box, fuses #46 and #50 are often related to the O2 sensors) to rule out a simple electrical issue.
Installation Pro-Tip
Replacing an O2 sensor is a feasible DIY job. The most difficult part is often accessing the sensor and removing it if it's seized by rust. Always let the exhaust cool completely before starting. Spraying penetrating oil on the base of the old sensor can help loosen it. Using a special O2 sensor socket, which has a slot for the wire, is highly recommended and makes the job much easier. Most new sensors come with anti-seize compound pre-applied to the threads; if not, apply a small amount, being careful not to get any on the sensor tip itself.
🎬 Watch this step-by-step O2 sensor replacement walkthroughFrequently Asked Questions
How many oxygen sensors does my 2015-2019 Sierra 1500 have?
All V6 and V8 models from this generation have four oxygen sensors: two upstream (Bank 1 Sensor 1 and Bank 2 Sensor 1) and two downstream (Bank 1 Sensor 2 and Bank 2 Sensor 2).
What is the difference between an upstream and a downstream sensor?
Upstream sensors are located before the catalytic converter and are the primary sensors used by the engine computer to adjust the air-fuel ratio. Downstream sensors are located after the catalytic converter and primarily monitor the converter's efficiency. They are not interchangeable.
What do the bank and sensor numbers mean (e.g., Bank 1 Sensor 1)?
"Bank 1" refers to the side of the engine that contains cylinder #1, which is the driver's side on your GMC Sierra. "Bank 2" is the passenger's side. 🎬 See this guide to locate Bank 1 Sensor 1 "Sensor 1" always refers to the upstream sensor (before the catalytic converter), and "Sensor 2" refers to the downstream sensor (after the converter).
Do I need to replace all four sensors at once?
No, you only need to replace the specific sensor that has failed. Your mechanic or a code scanner can tell you which sensor is causing the issue. However, since they have similar lifespans, if one fails at high mileage, others may not be far behind.
Do I need to reset the computer after replacing the sensor?
Yes, it is best practice to clear the diagnostic trouble codes (DTCs) from the engine computer using a scan tool after replacement. This will turn off the Check Engine Light and allow the system to properly calibrate with the new sensor.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12687606 12637679
Your truck is equipped with four heated, 4-wire oxygen sensors. The V6 and V8 engines use two upstream sensors (Bank 1 Sensor 1, Bank 2 Sensor 1) and two downstream sensors (Bank 1 Sensor 2, Bank 2 Sensor 2). Bank 1 is the driver's side, Bank 2 is the passenger's side.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- GMC Sierra 1500: