AutoCodes – Nissan – P0139 2011 Nissan Pathfinder

P0139 2011 Nissan Pathfinder Code - HO2S12 Slow Response

Quick Answer

The Heated Oxygen Sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection. 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 2011 Nissan Pathfinder indicates HO2S12 Slow Response.
Common causes: Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection.
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.

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Code Popularity 3,328

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 25, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0139 2011 Nissan Pathfinder Description

The Heated Oxygen Sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

OBDII Code P0139 2011 Nissan Pathfinder - HO2S12 Slow Response - AutoCodes.com — P0139 2011 Nissan Pathfinder Code - HO2S12 Slow Response

What does this mean?

What are the Possible Causes of the DTC P0139 2011 Nissan Pathfinder?

Faulty Rear Heated Oxygen Sensor Bank 1
Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

How to Fix the DTC P0139 2011 Nissan Pathfinder?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0139 2011 Nissan Pathfinder code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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 2011 Nissan Pathfinder Code

1. What does OBDII code P0139 for a 2011 Nissan Pathfinder mean?

- This code, also known as HO2S12 Slow Response, indicates that the oxygen sensor in bank 1 sensor 2 is not responding as quickly as expected.

2. What are the common symptoms of OBDII code P0139 on a 2011 Nissan Pathfinder?

- Common symptoms include poor fuel economy, rough idling, hesitation during acceleration, and the illumination of the Check Engine Light.

3. What are the potential causes of OBDII code P0139 on a 2011 Nissan Pathfinder?

- The code can be triggered by issues such as a faulty oxygen sensor, wiring problems, exhaust leaks, or issues with the engine's air-fuel ratio.

4. How can I diagnose the OBDII code P0139 on my 2011 Nissan Pathfinder?

- Diagnosing this code typically involves checking the oxygen sensor's wiring, inspecting for exhaust leaks, and testing the sensor's response time using a scan tool.

5. Can I drive my 2011 Nissan Pathfinder with an active P0139 trouble code?

- While the vehicle may still be driveable with this code, it is recommended to address the issue promptly to prevent potential damage to the catalytic converter and ensure optimal engine performance.

6. How can I repair OBDII code P0139 on my 2011 Nissan Pathfinder?

- Repair options may include replacing the oxygen sensor, repairing any damaged wiring, fixing exhaust leaks, or addressing any underlying issues affecting the air-fuel mixture.

7. How much does it typically cost to fix OBDII code P0139 on a 2011 Nissan Pathfinder?

- The cost of repair can vary depending on the specific cause of the code and the labor rates in your area. Replacement oxygen sensors can range from $50 to $200, with additional costs for labor.

8. Are there any maintenance tips to prevent OBDII code P0139 on a 2011 Nissan Pathfinder?

- Regular maintenance, such as replacing oxygen sensors at recommended intervals, inspecting for exhaust leaks, and using quality fuel, can help prevent issues that trigger this code.

9. Can resetting the Check Engine Light clear the OBDII code P0139 on a 2011 Nissan Pathfinder?

- Resetting the Check Engine Light may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to return after driving cycles.

10. Is it safe to ignore OBDII code P0139 on a 2011 Nissan Pathfinder?

- Ignoring this code can lead to decreased fuel efficiency, potential engine damage, and may cause the vehicle to fail emissions tests. It is advisable to address the issue promptly.