AutoCodes – Nissan – P0139 2008 Nissan Sentra

P0139 2008 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 2008 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 2,331

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 Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0139 2008 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 2008 Nissan Sentra - HO2S12 Slow Response - AutoCodes.com — P0139 2008 Nissan Sentra Code - HO2S12 Slow Response

What does this mean?

What are the Possible Causes of the DTC P0139 2008 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 2008 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 2008 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 2008 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 2008 Nissan Sentra Code

1. What are common symptoms of OBDII code P0139 on a 2008 Nissan Sentra?

- Common symptoms include poor fuel efficiency, rough idling, and a noticeable drop in engine performance.

2. What does the OBDII code P0139 for a 2008 Nissan Sentra indicate?

- The code P0139 indicates a slow response from the downstream oxygen sensor (HO2S12) in Bank 1.

3. What are the potential causes of OBDII code P0139 on a 2008 Nissan Sentra?

- The possible causes include a faulty oxygen sensor, wiring issues, exhaust system leaks, or an engine mechanical problem.

4. How can I diagnose the cause of OBDII code P0139 on my 2008 Nissan Sentra?

- A thorough inspection of the oxygen sensor, wiring harness, and exhaust system, as well as performing a live data scan with an OBDII scanner, can help diagnose the issue.

5. Can I continue driving my 2008 Nissan Sentra with OBDII code P0139?

- It is not recommended to drive the vehicle for an extended period with this code as it can lead to further damage and reduced fuel efficiency.

6. What is the average cost to repair OBDII code P0139 on a 2008 Nissan Sentra?

- Repair costs for this code can vary depending on the exact cause, but they typically range from $200 to $500, including parts and labor.

7. How long does it take to repair OBDII code P0139 on a 2008 Nissan Sentra?

- The repair time can vary based on the cause of the issue, but a skilled mechanic can usually diagnose and fix the problem within a few hours to a day.

8. Can I reset the OBDII code P0139 on my 2008 Nissan Sentra using an OBDII scanner?

- Yes, you can reset the code using an OBDII scanner, but it is crucial to address the underlying issue causing the code to prevent it from reoccurring.

9. Are there any DIY repair tips for OBDII code P0139 on a 2008 Nissan Sentra?

- While some simple checks like inspecting the oxygen sensor wiring connections can be done by DIY enthusiasts, it is recommended to consult a professional mechanic for accurate diagnosis and repair.

10. Will fixing OBDII code P0139 improve the overall performance of my 2008 Nissan Sentra?

- Yes, resolving the P0139 code should lead to improved fuel efficiency, smoother engine operation, and overall better performance of your Nissan Sentra.