AutoCodes – Nissan – P0139 2006 Nissan Pathfinder

P0139 2006 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 2006 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 2,229

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 2006 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 2006 Nissan Pathfinder - HO2S12 Slow Response - AutoCodes.com — P0139 2006 Nissan Pathfinder Code - HO2S12 Slow Response

What does this mean?

What are the Possible Causes of the DTC P0139 2006 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 2006 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 2006 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 2006 Nissan Pathfinder Code

1. What does the OBDII code P0139 for a 2006 Nissan Pathfinder mean?

- The code P0139 indicates a slow response from the heated oxygen sensor (HO2S12) located after the catalytic converter in Bank 1 Sensor 2.

2. What are the common symptoms of a P0139 code in a 2006 Nissan Pathfinder?

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

3. What are the possible causes of a P0139 code in a 2006 Nissan Pathfinder?

- The causes may include a faulty oxygen sensor, wiring issues, exhaust leaks, a malfunctioning catalytic converter, or an engine vacuum leak.

4. How can I diagnose a P0139 code in my 2006 Nissan Pathfinder?

- Diagnosing a P0139 code typically involves inspecting the HO2S12 sensor, checking for wiring damage, testing the sensor's response time, and scanning for any related codes.

5. How can I repair a P0139 code in my 2006 Nissan Pathfinder?

- Repair options may involve replacing the HO2S12 sensor, repairing damaged wiring, fixing any exhaust leaks, addressing catalytic converter issues, or resolving vacuum leaks.

6. Is it safe to continue driving with a P0139 code in my 2006 Nissan Pathfinder?

- While the vehicle may still be operational with a P0139 code, it is advisable to address the issue promptly to prevent potential damage to the engine and the catalytic converter.

7. Can I reset the check engine light after fixing a P0139 code on my 2006 Nissan Pathfinder?

- Yes, once the underlying issue causing the P0139 code is resolved, the check engine light can be reset using an OBDII scanner or disconnecting the vehicle's battery for a few minutes.

8. How often does the HO2S12 sensor need to be replaced in a 2006 Nissan Pathfinder?

- The HO2S12 sensor typically does not need frequent replacement unless it fails or shows signs of deterioration, which can vary depending on driving conditions and maintenance.

9. What are some preventive measures to avoid a P0139 code in a 2006 Nissan Pathfinder?

- Regular maintenance, such as checking and replacing oxygen sensors as recommended, addressing exhaust system issues promptly, and using quality fuel, can help prevent P0139 codes.

10. Will a P0139 code affect the emissions test for my 2006 Nissan Pathfinder?

- Yes, a P0139 code can cause the vehicle to fail an emissions test due to improper oxygen sensor readings, which may result in increased emissions levels.