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P0139 2012 Nissan Sentra Code - HO2S12 Slow Response

Quick Answer

The P0139 diagnostic trouble code (DTC) for a 2012 Nissan Sentra refers to a slow response from the downstream oxygen sensor (HO2S12). Common causes include Faulty downstream oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P0139 2012 Nissan Sentra indicates HO2S12 Slow Response.
Common causes
Common causes include Faulty downstream oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
What is this?
Table of contents Created and updated by William Orellana on Sep 13, 2024
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Code P0139 2012 Nissan Sentra Description

The P0139 diagnostic trouble code (DTC) for a 2012 Nissan Sentra refers to a slow response from the downstream oxygen sensor (HO2S12). The downstream oxygen sensor is located after the catalytic converter and is responsible for monitoring the efficiency of the catalytic converter in reducing harmful emissions. When the sensor detects a slow response, it means that the sensor is not providing accurate and timely feedback to the engine control module (ECM) regarding the air-fuel mixture. This can lead to a variety of issues affecting the vehicle's performance, fuel efficiency, and emissions.

OBDII Code P0139 2012 Nissan Sentra - HO2S12 Slow Response
P0139 2012 Nissan Sentra Code - HO2S12 Slow Response

Common Causes of P0139 2012 Nissan Sentra

  1. Faulty downstream oxygen sensor
  2. Wiring or connector issues
  3. Exhaust leaks near the sensor
  4. Contaminated sensor
  5. ECM software issues

Symptoms of P0139 2012 Nissan Sentra

  1. Decreased fuel efficiency
  2. Rough idle or stalling
  3. Engine misfires
  4. Check Engine Light illuminated
  5. Increased emissions

How to Fix P0139 2012 Nissan Sentra

  1. Diagnose the issue by using a scan tool to monitor the downstream oxygen sensor's response time.
  2. Inspect the sensor, wiring, and connectors for any damage or corrosion.
  3. Replace the downstream oxygen sensor if it is faulty or contaminated.
  4. Repair any exhaust leaks near the sensor.
  5. Clear the DTC and perform a test drive to verify that the issue has been resolved.

Cost to Fix P0139 2012 Nissan Sentra

The typical repair costs for addressing a P0139 code on a 2012 Nissan Sentra can range from $150 to $400, depending on the specific cause of the issue and the cost of parts and labor. This estimate includes the cost of a new downstream oxygen sensor, any necessary wiring repairs, and the labor involved in diagnosing and repairing the problem. It's important to note that the actual cost may vary based on the location of the repair shop, the vehicle's make and model, and the specific engine type. Additionally, diagnostic time and labor rates can vary, with hourly rates typically ranging from $80 to $150. It's recommended to obtain quotes from local auto repair shops for a more accurate cost estimate.

What does this mean?

Tech Notes for P0139 2012 Nissan Sentra

Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.

When is the Code Detected?

The P0139 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor takes more time to respond between rich and lean than the specified time.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0139 2012 Nissan Sentra Code

1. What does the OBDII code P0139 for a 2012 Nissan Sentra indicate?

The code P0139 on a 2012 Nissan Sentra refers to a Slow Response from the downstream oxygen sensor (HO2S12).

2. What are the common symptoms of the HO2S12 Slow Response code in a 2012 Nissan Sentra?

Common symptoms of the P0139 code in a 2012 Nissan Sentra may include poor fuel economy, rough idling, and potential engine misfires.

3. What are the possible causes of the P0139 code on a 2012 Nissan Sentra?

Possible causes of the P0139 code on a 2012 Nissan Sentra include a faulty oxygen sensor, wiring issues, exhaust leaks, or a problem with the engine's fuel system.

4. How can I diagnose the cause of the P0139 code on my 2012 Nissan Sentra?

Diagnosing the P0139 code on a 2012 Nissan Sentra involves inspecting the oxygen sensor and its wiring, checking for exhaust leaks, and testing the engine's fuel system for proper operation.

5. Can I continue driving my 2012 Nissan Sentra with the P0139 code?

It is not recommended to drive your 2012 Nissan Sentra with the P0139 code as it can lead to decreased fuel efficiency and potential damage to the engine over time.

6. How can I repair the HO2S12 Slow Response code on my 2012 Nissan Sentra?

Repairing the P0139 code on a 2012 Nissan Sentra may involve replacing the downstream oxygen sensor, repairing any wiring issues, fixing exhaust leaks, or addressing fuel system problems.

7. Is it possible to reset the OBDII code P0139 on a 2012 Nissan Sentra without repairing the issue?

While you can clear the P0139 code on a 2012 Nissan Sentra with an OBDII scanner, it is important to address the underlying problem to prevent the code from reoccurring.

8. How much does it cost to fix the P0139 code on a 2012 Nissan Sentra?

The cost of fixing the P0139 code on a 2012 Nissan Sentra can vary depending on the specific cause of the issue, but it may range from $100 to $300 for parts and labor.

9. Can a DIY enthusiast repair the P0139 code on a 2012 Nissan Sentra?

If you have the necessary tools and experience working on vehicles, you may be able to replace the downstream oxygen sensor or address wiring issues causing the P0139 code on your 2012 Nissan Sentra.

10. How often should I check the oxygen sensors in my 2012 Nissan Sentra to prevent the P0139 code from appearing?

It is recommended to inspect and potentially replace the oxygen sensors in your 2012 Nissan Sentra as part of regular maintenance every 60,000 to 90,000 miles to help prevent the P0139 code from appearing.

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