AutoCodes – Nissan – P0139 2005 Nissan Altima Sedan

P0139 2005 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 2005 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 4,132

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 2005 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 2005 Nissan Altima Sedan - HO2S12 Slow Response - AutoCodes.com — P0139 2005 Nissan Altima Sedan Code - HO2S12 Slow Response

What does this mean?

What are the Possible Causes of the DTC P0139 2005 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 2005 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 2005 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 2005 Nissan Altima Sedan Code

1. What does the OBDII code P0139 on a 2005 Nissan Altima Sedan mean?

- It indicates a slow response from the HO2S12 (Heated Oxygen Sensor Bank 1 Sensor 2) located after the catalytic converter.

2. What are the common symptoms of a P0139 code in a 2005 Nissan Altima Sedan?

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

3. What are the possible causes of a HO2S12 slow response code on a 2005 Nissan Altima Sedan?

- Causes may include a faulty HO2S12 sensor, wiring issues, exhaust leaks, engine misfires, or a failing catalytic converter.

4. How can I diagnose a P0139 code on my 2005 Nissan Altima Sedan?

- Diagnose the code by checking the wiring harness for damage, testing the HO2S12 sensor's voltage output, and inspecting the exhaust system for leaks.

5. Can a P0139 code be triggered by a loose gas cap on a 2005 Nissan Altima Sedan?

- No, a P0139 code is specifically related to the HO2S12 sensor's slow response and is not caused by a loose gas cap.

6. Is it safe to continue driving a 2005 Nissan Altima Sedan with a P0139 code?

- While the vehicle may still be operational, driving with a P0139 code can lead to decreased fuel efficiency and potential damage to the catalytic converter over time.

7. How can I repair a P0139 code on my 2005 Nissan Altima Sedan?

- Repair options include replacing the HO2S12 sensor, repairing any damaged wiring, fixing exhaust leaks, addressing engine misfires, or replacing a failing catalytic converter.

8. Can I reset the Check Engine Light after fixing a P0139 code on my 2005 Nissan Altima Sedan?

- Yes, the Check Engine Light can be reset using an OBDII scanner after the repair to clear the P0139 code and monitor for any recurring issues.

9. How much does it cost to repair a P0139 code on a 2005 Nissan Altima Sedan at a mechanic?

- Repair costs can vary depending on the specific issue, but expect to pay anywhere from $100 to $400 for parts and labor to address a HO2S12 slow response code.

10. Will a P0139 code on a 2005 Nissan Altima Sedan cause the vehicle to fail an emissions test?

- Yes, a P0139 code typically indicates an issue with the emissions control system, which can lead to a failed emissions test until the problem is resolved.