AutoCodes – Nissan – P0139 2011 Nissan Sentra

P0139 2011 Nissan Sentra 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 Sentra 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 2,696

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 Apr 12, 2019

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

What does this mean?

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

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 Sentra?

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 Sentra 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.

Need more information about the P0139 2011 Nissan Sentra 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 2011 Nissan Sentra Code

What does the OBDII code P0139 mean on a 2011 Nissan Sentra?

Code P0139 indicates that the Oxygen Sensor in bank 1, sensor 2 (HO2S12) is responding more slowly than expected to changes in fuel mixture, suggesting a fault in the sensor or its circuit.

What are common symptoms of code P0139 in a 2011 Nissan Sentra?

Symptoms may include a check engine light, poor fuel economy, rough engine idle, or a noticeable drop in engine performance.

What can cause the OBDII code P0139 to appear on my 2011 Nissan Sentra?

Potential causes include a faulty oxygen sensor, leaks in the exhaust system, problems with the fuel delivery system, or an issue with the sensor's electrical connections or wiring.

How do I fix the OBDII code P0139 in my 2011 Nissan Sentra?

To fix this issue, check and replace the oxygen sensor if necessary, repair any leaks in the exhaust system, ensure proper fuel mixture, and check the wiring and connectors for damage or corrosion.

Is it safe to drive my 2011 Nissan Sentra with the OBDII code P0139?

While you can still drive with P0139, it's advisable to address the issue soon. Ignoring it can lead to reduced fuel efficiency, increased emissions, and potential damage to other components like the catalytic converter.

How do I confirm that the oxygen sensor is the problem with code P0139 on my 2011 Nissan Sentra?

You can diagnose this by checking the sensor's performance with an OBDII scanner that displays live data. A slower response time compared to specifications would suggest the sensor needs replacing.

What tools are needed to diagnose the P0139 code on a 2011 Nissan Sentra?

You will need an OBDII scanner capable of reading sensor data, a digital multimeter for electrical tests, and basic hand tools to access the sensor.

Could a dirty air filter cause the P0139 code in a 2011 Nissan Sentra?

While a dirty air filter can affect overall engine performance, it is unlikely to directly trigger a P0139 code. This code specifically relates to the response time of the oxygen sensor.

What is the estimated repair cost for P0139 in a 2011 Nissan Sentra?

The cost can vary widely, but replacing an oxygen sensor can cost anywhere from $200 to $400 depending on parts and labor rates. Additional repairs like fixing exhaust leaks or wiring issues can increase this cost.