AutoCodes – Nissan – P0139 2009 Nissan Altima Sedan

P0139 2009 Nissan Altima Sedan 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 2009 Nissan Altima Sedan 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 3,693

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 2009 Nissan Altima Sedan 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 2009 Nissan Altima Sedan - HO2S12 Slow Response - AutoCodes.com — P0139 2009 Nissan Altima Sedan Code - HO2S12 Slow Response

What does this mean?

What are the Possible Causes of the DTC P0139 2009 Nissan Altima Sedan?

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 2009 Nissan Altima Sedan?

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 2009 Nissan Altima Sedan 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 2009 Nissan Altima Sedan Code

1. What are the common symptoms of OBDII code P0139 in a 2009 Nissan Altima Sedan?

- Common symptoms include poor fuel economy, rough idling, hesitation during acceleration, and the illumination of the check engine light.

2. What does the OBDII code P0139 for a 2009 Nissan Altima Sedan indicate?

- The code P0139 indicates that the downstream oxygen sensor (HO2S12) is experiencing a slow response time.

3. What are the possible causes of OBDII code P0139 in a 2009 Nissan Altima Sedan?

- Possible causes include a faulty oxygen sensor, wiring issues in the oxygen sensor circuit, exhaust leaks, or an engine running too rich or too lean.

4. How do I diagnose the cause of OBDII code P0139 in my 2009 Nissan Altima Sedan?

- To diagnose the issue, you can use an OBDII scanner to read the code and check the oxygen sensor's voltage readings. Additionally, inspect the sensor's wiring and the exhaust system for any leaks.

5. Can I continue driving my 2009 Nissan Altima Sedan with OBDII code P0139?

- It is not recommended to continue driving with the code P0139 as it can lead to further damage to the catalytic converter and engine components.

6. How can I repair OBDII code P0139 in my 2009 Nissan Altima Sedan?

- The repair typically involves replacing the downstream oxygen sensor (HO2S12) with a new one and ensuring that the wiring connections are secure and free of damage.

7. Are there any DIY tips for fixing OBDII code P0139 in a 2009 Nissan Altima Sedan?

- While replacing the oxygen sensor can be done as a DIY repair, it's important to have the correct tools and follow the manufacturer's instructions for proper installation.

8. How much does it cost to repair OBDII code P0139 in a 2009 Nissan Altima Sedan?

- The cost of repairing OBDII code P0139 can vary depending on the labor rates and the price of the oxygen sensor. On average, the repair can cost between $150 to $300.

9. Will resetting the check engine light resolve OBDII code P0139 in a 2009 Nissan Altima Sedan?

- Resetting the check engine light may temporarily turn it off, but it will not fix the underlying issue causing the code. It's important to diagnose and repair the problem to prevent further issues.

10. How often should I replace the oxygen sensors in my 2009 Nissan Altima Sedan to prevent OBDII code P0139?

- Oxygen sensors typically last around 60,000 to 90,000 miles. It's recommended to follow the manufacturer's maintenance schedule and replace them as needed to prevent issues like code P0139.