AutoCodes – Nissan – P0139 2005 Nissan Maxima

P0139 2005 Nissan Maxima 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 Maxima 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 5,623

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

What does this mean?

What are the Possible Causes of the DTC P0139 2005 Nissan Maxima?

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 Maxima?

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 Maxima 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 2005 Nissan Maxima 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 2005 Nissan Maxima Code

What does the OBDII code P0139 mean for a 2005 Nissan Maxima?

P0139 indicates that the oxygen sensor (HO2S12) is experiencing a slow response time, meaning it is not reacting quickly enough to changes in the exhaust gas composition.

What symptoms might I notice with a P0139 code?

Common symptoms include poor fuel economy, rough idling, decreased engine performance, and possible triggering of the check engine light.

What are the potential causes of the P0139 code?

Potential causes include a faulty oxygen sensor, exhaust leaks, wiring issues, or problems with the engine's air-fuel mixture.

Can driving with a P0139 code damage my vehicle?

While it may not cause immediate damage, ignoring the issue can lead to poor engine performance and increased emissions, which could result in more serious problems over time.

How can I diagnose the P0139 code?

Start by inspecting the oxygen sensor and its wiring for damage or disconnection. Use a multimeter to test the sensor's voltage and response time. Check for exhaust leaks and verify the engine's air-fuel mixture.

What is the typical repair for a P0139 code?

The most common repair is replacing the faulty oxygen sensor. Additionally, addressing any exhaust leaks or wiring issues may be necessary.

Should I clear the P0139 code after repairs?

Yes, after completing the necessary repairs, you should clear the code using an OBDII scanner and then take the vehicle for a test drive to see if the code returns.

How much might it cost to fix a P0139 code on a 2005 Nissan Maxima?

Repair costs can vary widely but typically range from $100 to $400, depending on whether you need to replace the oxygen sensor or address other underlying issues.

Can I drive my 2005 Nissan Maxima with a P0139 code?

While it is possible to drive the vehicle, it is advisable to address the issue promptly to avoid further damage and reduce emissions.