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P0139 2008 Nissan Pathfinder Code - HO2S12 Slow Response

Quick Answer

The P0139 diagnostic trouble code (DTC) for a 2008 Nissan Pathfinder refers to a slow response from the downstream oxygen sensor (HO2S12). Common causes include Faulty downstream oxygen sensor (HO2S12), Wiring or connector issues in the oxygen sensor circuit, 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 2008 Nissan Pathfinder indicates HO2S12 Slow Response.
Common causes
Common causes include Faulty downstream oxygen sensor (HO2S12), Wiring or connector issues in the oxygen sensor circuit, 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 15, 2024
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Code P0139 2008 Nissan Pathfinder Description

The P0139 diagnostic trouble code (DTC) for a 2008 Nissan Pathfinder refers to a slow response from the downstream oxygen sensor (HO2S12). The downstream oxygen sensor is responsible for monitoring the efficiency of the catalytic converter by measuring the oxygen content in the exhaust gases after they have passed through the converter. A slow response from this sensor can indicate issues with the catalytic converter's performance or other related components.

OBDII Code P0139 2008 Nissan Pathfinder - HO2S12 Slow Response
P0139 2008 Nissan Pathfinder Code - HO2S12 Slow Response

Common Causes of P0139 2008 Nissan Pathfinder

  1. Faulty downstream oxygen sensor (HO2S12)
  2. Wiring or connector issues in the oxygen sensor circuit
  3. Exhaust leaks near the sensor
  4. Contaminated or damaged catalytic converter
  5. ECM software or hardware issues

Symptoms of P0139 2008 Nissan Pathfinder

  1. Check engine light illuminated
  2. Decreased fuel efficiency
  3. Rough idling or stalling
  4. Poor engine performance
  5. Failed emissions test

How to Fix P0139 2008 Nissan Pathfinder

  1. Diagnose the code using an OBD-II scanner to confirm the P0139 DTC.
  2. Inspect the downstream oxygen sensor and its wiring for any damage or corrosion.
  3. Check for exhaust leaks near the sensor and repair as necessary.
  4. Test the catalytic converter for proper function and replace if needed.
  5. Clear the code from the ECM and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0139 2008 Nissan Pathfinder

The cost of repairing a P0139 code on a 2008 Nissan Pathfinder can vary depending on the specific cause of the issue. In general, replacing an oxygen sensor can cost between $200 and $300, including parts and labor. If the catalytic converter needs to be replaced, the cost can range from $500 to $1500 or more, depending on the type of converter and the vehicle's make and model. Additional costs may include diagnostic time and labor rates, which can vary between auto repair shops. It's recommended to obtain quotes from local shops to get a more accurate estimate for the repair.

What does this mean?

Tech Notes for P0139 2008 Nissan Pathfinder

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.

Need more information about the P0139 2008 Nissan Pathfinder code?

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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 2008 Nissan Pathfinder Code

1. What does the OBDII code P0139 on a 2008 Nissan Pathfinder indicate?

The code P0139 for a 2008 Nissan Pathfinder specifically refers to a fault with the HO2S12 sensor, indicating a slow response from the sensor.

2. What are the common symptoms of a HO2S12 slow response issue in a 2008 Nissan Pathfinder?

Common symptoms of a HO2S12 slow response issue include poor fuel efficiency, rough idling, engine misfires, and possibly a noticeable decrease in engine performance.

3. What are the possible causes of the HO2S12 slow response code on a 2008 Nissan Pathfinder?

Potential causes of a HO2S12 slow response code in a 2008 Nissan Pathfinder include a faulty oxygen sensor, wiring issues, exhaust leaks, or a problem with the engine's air-fuel mixture.

4. How can I diagnose the HO2S12 slow response problem in my 2008 Nissan Pathfinder?

Diagnosing a HO2S12 slow response issue typically involves checking the oxygen sensor's wiring, inspecting for exhaust leaks, and using a scan tool to monitor sensor data for proper response times.

5. Can I still drive my 2008 Nissan Pathfinder with the P0139 code present?

While it may be possible to drive your vehicle with the P0139 code present, it is not recommended as it can lead to decreased fuel efficiency and potential engine performance issues.

6. How can I repair a HO2S12 slow response problem in my 2008 Nissan Pathfinder?

Repairing a HO2S12 slow response issue may involve replacing the oxygen sensor, repairing any damaged wiring, fixing exhaust leaks, or addressing any issues with the air-fuel mixture.

7. Is it necessary to reset the OBDII system after repairing the P0139 code on a 2008 Nissan Pathfinder?

Yes, it is recommended to reset the OBDII system after repairing the P0139 code to clear the fault code and ensure that the issue has been resolved successfully.

8. Can a DIY enthusiast fix the HO2S12 slow response problem in a 2008 Nissan Pathfinder?

Depending on the DIY enthusiast's skill level and access to tools, it may be possible to address the HO2S12 slow response problem by following repair guides and using appropriate diagnostic equipment.

9. How much does it typically cost to repair a HO2S12 slow response issue in a 2008 Nissan Pathfinder?

The cost of repairing a HO2S12 slow response problem in a 2008 Nissan Pathfinder can vary depending on the specific cause of the issue, but it may range from $100 to $300 for parts and labor.

10. What steps can I take to prevent the recurrence of the P0139 code on my 2008 Nissan Pathfinder?

To prevent the recurrence of the P0139 code, regular maintenance of the oxygen sensors, monitoring the engine performance, and addressing any issues promptly can help maintain the vehicle's optimal performance.

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