AutoCodes – Infiniti – P0139 2006 Infiniti G35

P0139 2006 Infiniti G35 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 Infiniti G35 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 2,742

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 01, 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 Infiniti G35 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 Infiniti G35 - HO2S12 Slow Response - AutoCodes.com — P0139 2006 Infiniti G35 Code - HO2S12 Slow Response

What does this mean?

What are the Possible Causes of the DTC P0139 2006 Infiniti G35?

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 Infiniti G35?

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 Infiniti G35 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 Infiniti G35 Code

1. What does the OBDII code P0139 for a 2006 Infiniti G35 mean?

The code P0139 refers to a slow response from the HO2S12 sensor in the exhaust system of a 2006 Infiniti G35.

2. What are the common symptoms of the P0139 code in a 2006 Infiniti G35?

Common symptoms include poor engine performance, reduced fuel efficiency, rough idling, and the illumination of the check engine light.

3. What are the potential causes of the P0139 code in a 2006 Infiniti G35?

Possible causes include a faulty HO2S12 sensor, wiring issues, exhaust leaks, engine misfires, or a malfunctioning catalytic converter.

4. How can I diagnose the P0139 code in a 2006 Infiniti G35?

Diagnosis involves using an OBDII scanner to retrieve the code, checking the wiring and connections to the HO2S12 sensor, inspecting the sensor for damage, and testing the sensor's response time.

5. How can I repair the P0139 code in a 2006 Infiniti G35?

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

6. Can I drive my 2006 Infiniti G35 with the P0139 code?

It is not recommended to drive the vehicle with the P0139 code unresolved, as it can lead to further damage and potentially higher repair costs in the long run.

7. How much does it cost to fix the P0139 code in a 2006 Infiniti G35?

The cost of repairing the P0139 code can vary depending on the specific issue causing the code, but it may range from $100 to $500 or more, including parts and labor.

8. How often does the P0139 code occur in a 2006 Infiniti G35?

The P0139 code can occur sporadically or more frequently depending on the underlying issue causing the slow response from the HO2S12 sensor.

9. Can I reset the check engine light after fixing the P0139 code in my 2006 Infiniti G35?

Yes, after repairing the issue causing the P0139 code, you can use an OBDII scanner to reset the check engine light in your 2006 Infiniti G35.

10. Is the P0139 code a serious issue in a 2006 Infiniti G35?

While the P0139 code may not cause immediate harm to the vehicle, it is important to address the underlying problem promptly to prevent further damage and ensure optimal engine performance.