Chevrolet Impala Oxygen Sensor Guide for 2014-2020 Models

Understanding Your Impala's Oxygen Sensors

A failing oxygen sensor can cause real problems for your 2014-2020 Chevrolet Impala. It can hurt your gas mileage, make the engine run rough, and even damage expensive parts like the catalytic converter over time. This article will help you understand the symptoms of a bad sensor, choose the right aftermarket replacement, and know what to expect during the replacement process.

Your Impala has one of two engine options, which determines how many oxygen sensors you have:

• 2.5L 4-Cylinder: This engine has two oxygen sensors. One upstream (Bank 1, Sensor 1) and one downstream (Bank 1, Sensor 2).
• 3.6L V6: This engine has four oxygen sensors. Two upstream sensors (Bank 1, Sensor 1 and Bank 2, Sensor 1) and two downstream sensors (Bank 1, Sensor 2 and Bank 2, Sensor 2). Bank 2 is the cylinder bank closer to the firewall.

Symptoms of a Failing Oxygen Sensor

When an oxygen sensor goes bad, your car will usually let you know. Here are the most common signs:

• Check Engine Light: This is the most common symptom. The light will come on when the computer detects a problem with the sensor's signal. Common trouble codes include P0131, P0135, P0171 (System Too Lean), and P0174.
• Poor Fuel Economy: A bad sensor can't provide the right information, often causing the engine to use more fuel than it needs.
• Rough Idle and Misfires: The engine may run rough, hesitate, or misfire because the air-fuel mixture is incorrect.
• Failed Emissions Test: A bad O2 sensor is a common reason for failing a smog check.
• Bad Smell: In some cases, you might notice a harsh, rotten-egg smell from the exhaust, which indicates the catalytic converter is not working efficiently due to the bad sensor data.

Choosing the Right Aftermarket Oxygen Sensor

Not all aftermarket brands are the same. For a critical part like an oxygen sensor, quality matters. Here’s a breakdown of the available brands, from top-tier to budget-friendly.

Tier 1: OEM and Premium Aftermarket

These brands are known to be Original Equipment (OE) suppliers for GM or have a reputation for matching or exceeding OE quality. They are the safest bet for reliability and performance.

• ACDelco: This is GM's official brand. However, it's widely known that ACDelco often sources its sensors from other manufacturers, primarily Denso. You are paying for the GM-approved part, which is often a re-boxed Denso sensor.
• Denso: A major OE supplier for many carmakers, including GM. Many in the GM community consider Denso the go-to replacement, as you are often buying the exact same part as the ACDelco one, but without the higher price.
• Delphi: Historically a primary parts supplier for General Motors. Delphi sensors are considered a high-quality, OE-level choice with a strong reputation.
• NGK / NTK: NTK is the sensor division of NGK. They are a world-leading OE sensor manufacturer and are known for their high quality and reliability, putting them on par with Denso.

Tier 2: Reputable Aftermarket

These brands are well-known in the aftermarket and offer a good balance of quality and price. They are a solid choice for most repairs.

• Bosch: Bosch invented the modern oxygen sensor and is a massive OE supplier worldwide. However, some GM owners in forums have reported mixed results, suggesting potential calibration differences with GM computers. While many use them without issue, sticking with Denso, Delphi, or NGK is often seen as a safer bet for GM vehicles.

Tier 3: Budget Brands

These brands focus on providing the lowest-cost option. While they can work, their longevity and the precision of their readings may not match the higher-tier brands.

• Walker Products: A well-known exhaust and emissions parts company offering budget-friendly options.
• DriveWire: Another brand focused on affordability.

Cost to Replace an Impala Oxygen Sensor

Frequently Asked Questions