Where to Find the O2 Sensor on a 2013 Hyundai Elantra

The oxygen (O2) sensors on a 2013 Hyundai Elantra are located in the exhaust system: one (upstream) is mounted in the exhaust manifold near the engine, and one or more (downstream) are positioned further back in the exhaust pipe after the catalytic converter, depending on engine and market configuration. Understanding which sensor is which is crucial for accurate diagnosis and safe replacement.

Understanding the O2 Sensor System on the 2013 Elantra

The 2013 Hyundai Elantra uses O2 sensors to monitor exhaust gases and help the engine control module (ECM) adjust the air–fuel mixture for efficiency, emissions, and performance. When a check-engine light appears with codes related to oxygen sensors, knowing the exact physical locations helps determine whether you’re dealing with the upstream (Sensor 1) or downstream (Sensor 2) unit.

Typical O2 Sensor Locations on the 2013 Hyundai Elantra

While exact positioning can vary slightly by engine type and emissions package, most 2013 Elantras sold in North America use the 1.8L 4-cylinder engine and share the same basic sensor layout. Below is a detailed look at the most common configuration found on this model year.

Upstream O2 Sensor (Sensor 1)

The upstream O2 sensor, also called Sensor 1 or the air–fuel ratio sensor, is critical for mixture control. It is placed before the catalytic converter so it can monitor exhaust gases directly as they leave the engine.

The following points describe exactly where to find the upstream O2 sensor on a 2013 Hyundai Elantra and how to visually confirm you have the correct component.

• Engine bay location: The upstream O2 sensor is threaded into the exhaust manifold at the front of the engine, on the side closest to the radiator.
• View from above: With the hood open, look down behind the radiator and cooling fans toward the rear of the engine compartment; the exhaust manifold is shielded with a metal heat shield, and the sensor protrudes from this area with a wire harness attached.
• Appearance: The sensor typically looks like a small metal “plug” or probe screwed into the manifold, with a thick insulated wire leading to a plastic electrical connector.
• Before the catalytic converter: This sensor is positioned upstream of (ahead of) the catalytic converter; it measures raw exhaust as it exits the engine.
• Electrical connector location: The connector is usually clipped to a bracket or wiring harness at the top or side of the engine. Following the sensor wire from the manifold will lead you to disconnect point.

By identifying the exhaust manifold and finding the threaded probe with an attached harness near the front of the engine, you can reliably locate the upstream O2 sensor on a 2013 Hyundai Elantra.

Downstream O2 Sensor (Sensor 2)

The downstream O2 sensor, or Sensor 2, monitors the efficiency of the catalytic converter by comparing exhaust gas readings after the catalyst to those taken before it. Its position is further along the exhaust system under the vehicle.

The points below outline where and how to find the downstream O2 sensor on a 2013 Hyundai Elantra and what to look for when inspecting from underneath.

• Underbody location: The downstream O2 sensor is mounted in the exhaust pipe after the catalytic converter, typically beneath the vehicle, roughly under the front seats or just behind the engine area.
• Access from below: To see it, the car usually needs to be safely raised on ramps or jack stands; from underneath, follow the exhaust pipe from the engine toward the rear until you see the catalytic converter and then the sensor threaded into the pipe just behind it.
• Just after the catalytic converter: Look for a bulged section in the exhaust system (the catalytic converter); the downstream sensor will be screwed into the pipe directly after this component.
• Similar appearance to upstream sensor: It also appears as a metal probe with a wire harness attached, routed up toward the underside of the cabin or firewall, with a plastic connector clipped to the body.
• Role in diagnostics, not mixture control: While physically similar, this sensor mostly verifies catalyst performance and helps set codes such as P0420 (catalyst system efficiency below threshold).

By tracing the exhaust path from the front of the car to the rear and identifying the catalytic converter, you can locate the downstream O2 sensor screwed into the pipe just behind this component.

Variations by Engine, Market, and Emissions Package

Most 2013 Elantras in the U.S. and Canada are equipped with a 1.8L Gamma engine, but there are regional variations (such as 1.6L engines, different trims, or specific emissions packages) that can slightly alter the layout or number of O2 sensors.

The following list explains the main factors that can change sensor count or positioning and how they may affect what you see when you inspect the vehicle.

• Engine type: The 1.8L gasoline engine commonly has one upstream and one downstream sensor. Some export models or different engines (e.g., 1.6L) can have similar layouts but with minor bracket or harness routing differences.
• Emissions standards: In markets with stricter emissions requirements, there may be additional monitoring hardware or slightly relocated sensor positions, although the general “before and after the catalytic converter” rule still applies.
• Aftermarket exhausts: Vehicles with modified or performance exhaust systems may have relocated bungs (threaded holes) for O2 sensors; in such cases, sensors might be slightly farther downstream or at a different angle.
• Heat shields and covers: Some models include additional heat shielding that can partially obscure the sensors, requiring removal of shields for clear access while the physical sensor locations remain essentially the same.

Despite these variations, on all standard 2013 Elantra configurations the upstream sensor remains in or near the exhaust manifold, and the downstream sensor is still found in the exhaust pipe after the catalytic converter.

Identifying “Bank 1 Sensor 1” vs. “Bank 1 Sensor 2”

Scan tools and trouble codes typically reference sensors as “Bank 1 Sensor 1” or “Bank 1 Sensor 2.” Since the 2013 Elantra’s inline 4-cylinder engine only has one cylinder bank, “Bank 1” simply means the only bank of cylinders.

The following explanations clarify how diagnostic terminology matches what you see on the car and helps guide accurate repairs.

• Bank 1 Sensor 1 (B1S1): This is the upstream sensor in the exhaust manifold, before the catalytic converter. Codes like P0131, P0132, or P2195 often refer to issues with this sensor or its circuit.
• Bank 1 Sensor 2 (B1S2): This is the downstream sensor located after the catalytic converter in the exhaust pipe. Codes like P0137 or P0138, or a catalyst-efficiency code like P0420, commonly relate to this sensor or its readings.
• Only one bank: Because there is no Bank 2 on an inline-4, any reference to a second bank in generic literature doesn’t apply to the 2013 Elantra.
• Location vs. function: Sensor 1 always means “before the catalytic converter,” and Sensor 2 always means “after the catalytic converter,” regardless of vehicle make or model.

Matching the diagnostic code terminology to physical locations—upstream in the manifold versus downstream after the catalytic converter—ensures you replace or inspect the correct sensor on the Elantra.

Visual and Safety Tips for Locating the Sensors

Finding the O2 sensors involves working around very hot exhaust components and sometimes getting under the vehicle. Safety and awareness of what you’re looking at are important before taking any action.

The points below offer practical guidance to help you safely confirm sensor locations on a 2013 Hyundai Elantra.

• Confirm the car is cool: Exhaust components can stay hot long after the engine is shut off. Always allow plenty of cooling time before reaching near the manifold or exhaust pipe.
• Use proper support: If you must go under the vehicle, use quality jack stands or ramps on a level surface—never rely on a jack alone.
• Trace the wiring: If unsure which threaded probe is an O2 sensor, follow the attached insulated wiring to an electrical connector; true O2 sensors will always have a harness and plug, not a simple bolt head.
• Look for the catalytic converter: Identify the catalytic converter as a larger, often oval-shaped section in the exhaust with heat shielding; sensors located immediately before and after this section are the upstream and downstream O2 sensors.
• Avoid forcing connectors: Most O2 sensor connectors have locking tabs; gently press or slide the lock rather than pulling on the wires to disconnect.

Using deliberate, cautious inspection—especially around hot metals and electrical connectors—helps you pinpoint both Elantra O2 sensors without damage or risk of injury.

Summary

On a 2013 Hyundai Elantra, the upstream O2 sensor (Bank 1 Sensor 1) is located in the exhaust manifold at the front of the engine, visible from the engine bay with a wire running to a nearby connector. The downstream O2 sensor (Bank 1 Sensor 2) is threaded into the exhaust pipe after the catalytic converter underneath the car. While minor variations may exist based on engine and market, these general locations hold for typical North American 1.8L models and align with how diagnostic codes reference the sensors. Knowing which sensor is which—and where they sit in relation to the catalytic converter—is essential for accurate diagnostics and safe replacement.

Where is the O2 oxygen sensor located?

Oxygen (O2cap O sub 2𝑂2) sensors are located in the vehicle’s exhaust system, with their exact position depending on whether they are “upstream” (before the catalytic converter) or “downstream” (after the catalytic converter). Modern vehicles typically have two or four sensors. The upstream sensor is mounted closer to the engine to monitor the air-fuel mixture, while the downstream sensor is mounted after the catalytic converter to check if the converter is working properly.
 
You can watch this video to see the locations of upstream and downstream O2 sensors: 55s1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · May 12, 2017
Upstream sensor (Sensor 1)

• Location: In the exhaust manifold or pipe before the catalytic converter, closer to the engine. 
• Function: It measures the oxygen in the raw exhaust gases to help the car’s computer adjust the air-fuel ratio for optimal combustion. 

Downstream sensor (Sensor 2)

• Location: In or after the catalytic converter.
• Function: It monitors the exhaust gases coming out of the catalytic converter to ensure it is functioning correctly. 

On V-type engines

• Engines with two banks of cylinders (like V6 or V8) will have a “bank 1” and a “bank 2,” each with an upstream and downstream sensor. 
• You can identify bank 1 by locating the #1 cylinder on the engine, which is where bank 1 begins. 
• Sensors are numbered according to their location on the exhaust path, with Sensor 1 always being the upstream sensor and Sensor 2 being the downstream sensor. 

This video explains the different sensor locations on a V-type engine: 1mBarbour’s Auto HelpYouTube · Jan 7, 2024

What is the most common problem on a 2013 Hyundai Elantra?

Owner Reported Trouble Spots

• Drive System.
• Noises/Leaks.
• Fuel System/Emissions.
• Engine Minor.
• Transmission Minor.
• Engine Major.
• Engine Electrical.
• Engine Cooling. Radiator, cooling fan, water pump, thermostat, antifreeze leaks, overheating.

Where is the oxygen sensor located on a Hyundai Elantra?

Free. We’re using a short extension with our ratchet. Once you get that on there. There it is.

How many O2 sensors does a Hyundai Elantra have?

There are two O2 sensors in the engine.