Engine-CodesNissan – P0139 2012 Nissan Altima Sedan

P0139 2012 Nissan Altima Sedan Code - HO2S12 Slow Response

Quick Answer

The P0139 diagnostic trouble code (DTC) for a 2012 Nissan Altima Sedan refers to a slow response from the downstream oxygen sensor (HO2S12). Common causes include Faulty Oxygen Sensor: The downstream oxygen sensor may be malfunctioning, leading to a slow response, Wiring Issues: Damaged or corroded wiring connections to the oxygen sensor can cause communication problems, Exhaust Leaks: Leaks in the exhaust system can affect the sensor's readings and response time. 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 Altima Sedan indicates HO2S12 Slow Response.
Common causes
Common causes include Faulty Oxygen Sensor: The downstream oxygen sensor may be malfunctioning, leading to a slow response, Wiring Issues: Damaged or corroded wiring connections to the oxygen sensor can cause communication problems, Exhaust Leaks: Leaks in the exhaust system can affect the sensor's readings and response time.
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.
Table of contents Created and updated by William Orellana on Sep 17, 2024
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Code P0139 2012 Nissan Altima Sedan Description

The P0139 diagnostic trouble code (DTC) for a 2012 Nissan Altima Sedan 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 and providing feedback to the engine control module (ECM) to adjust fuel mixture for optimal emissions and performance.

OBDII Code P0139 2012 Nissan Altima Sedan - HO2S12 Slow Response
P0139 2012 Nissan Altima Sedan Code - HO2S12 Slow Response

Common Causes of P0139 2012 Nissan Altima Sedan

  1. Faulty Oxygen Sensor: The downstream oxygen sensor may be malfunctioning, leading to a slow response.
  2. Wiring Issues: Damaged or corroded wiring connections to the oxygen sensor can cause communication problems.
  3. Exhaust Leaks: Leaks in the exhaust system can affect the sensor's readings and response time.
  4. Catalytic Converter Problems: Issues with the catalytic converter can impact the downstream oxygen sensor's performance.
  5. ECM Malfunction: A malfunctioning engine control module may not be able to properly interpret the sensor's feedback.

Symptoms of P0139 2012 Nissan Altima Sedan

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the vehicle's dashboard.
  2. Poor Fuel Economy: A slow response from the downstream oxygen sensor can lead to incorrect fuel mixture adjustments, resulting in decreased fuel efficiency.
  3. Rough Idle: The engine may experience rough idling or hesitation when the downstream oxygen sensor is not providing accurate feedback.
  4. Failed Emissions Test: If the vehicle's emissions are affected by the slow response from the oxygen sensor, it may fail an emissions test.

How to Fix P0139 2012 Nissan Altima Sedan

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the specific trouble code and further diagnose the cause of the slow response from the downstream oxygen sensor.
  2. Inspect Wiring: Check the wiring connections to the oxygen sensor for any damage or corrosion and repair or replace as needed.
  3. Test Oxygen Sensor: Test the downstream oxygen sensor to determine if it is functioning properly and replace if necessary.
  4. Check for Exhaust Leaks: Inspect the exhaust system for any leaks that could be affecting the sensor's readings and repair as needed.
  5. Verify Catalytic Converter Function: Ensure that the catalytic converter is functioning correctly and replace if necessary to prevent future issues with the oxygen sensor.

Cost to Fix P0139 2012 Nissan Altima Sedan

The typical repair costs for addressing a P0139 code on a 2012 Nissan Altima Sedan can vary depending on the specific cause of the issue. In general, replacing an oxygen sensor can cost between $100 and $300, including parts and labor. However, if additional repairs are needed, such as fixing wiring issues or replacing the catalytic converter, the total cost could be higher.

Tech Notes for P0139 2012 Nissan Altima Sedan

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 Altima Sedan Code

1. What does OBDII code P0139 on my 2012 Nissan Altima Sedan mean?

Code P0139 stands for "HO2S12 Slow Response," indicating a delayed response from the downstream oxygen sensor (HO2S12) in bank 1 sensor 2.

2. What are the common symptoms of a HO2S12 Slow Response error code?

Common symptoms include poor fuel economy, rough idle, engine misfires, and the illumination of the Check Engine Light on the dashboard.

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

Potential causes include a faulty oxygen sensor, wiring issues, exhaust leaks, engine misfires, vacuum leaks, or issues with the engine's air-fuel mixture.

4. How can I diagnose the source of a HO2S12 Slow Response code on my Nissan Altima?

Diagnosis typically involves inspecting the oxygen sensor, checking for wiring damage or corrosion, inspecting the exhaust system for leaks, and verifying the engine's fuel system components.

5. Can a P0139 code be triggered by a loose gas cap on a 2012 Nissan Altima Sedan?

While a loose gas cap can trigger other codes related to the evaporative emission system, it is unlikely to cause a HO2S12 Slow Response error code.

6. What are the potential repair options for resolving a P0139 code on a 2012 Nissan Altima Sedan?

Repair options may include replacing the downstream oxygen sensor, repairing damaged wiring, fixing exhaust leaks, addressing engine misfires, and ensuring proper air-fuel mixture.

7. Is it safe to continue driving my 2012 Nissan Altima Sedan with a P0139 code?

It is generally not recommended to ignore a P0139 code, as it can lead to reduced fuel efficiency and potential damage to the vehicle's catalytic converter over time.

8. How much does it typically cost to fix a P0139 code on a 2012 Nissan Altima Sedan?

The cost of repairs can vary depending on the specific cause of the code, but it may involve parts and labor expenses ranging from $100 to $300 or more.

9. Can I reset the Check Engine Light after fixing a P0139 code on my Nissan Altima Sedan?

Once the underlying issue triggering the code has been resolved, the Check Engine Light can be reset using an OBDII scanner or by disconnecting the car's battery for a few minutes.

10. Will a P0139 code on a 2012 Nissan Altima Sedan affect the vehicle's emissions or performance?

Yes, a P0139 code can impact emissions levels and engine performance, potentially leading to decreased fuel efficiency and increased harmful emissions if left unresolved.

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