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P0139 2004 Nissan Maxima Code - HO2S12 Slow Response

Quick Answer

The P0139 diagnostic trouble code (DTC) for a 2004 Nissan Maxima indicates a slow response from the downstream oxygen sensor (HO2S12). Common causes include Faulty downstream oxygen sensor, Wiring or connector issues in the oxygen sensor circuit, Exhaust leaks near the downstream oxygen sensor. 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 2004 Nissan Maxima indicates HO2S12 Slow Response.
Common causes
Common causes include Faulty downstream oxygen sensor, Wiring or connector issues in the oxygen sensor circuit, Exhaust leaks near the downstream oxygen sensor.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 18, 2024
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Code P0139 2004 Nissan Maxima Description

The P0139 diagnostic trouble code (DTC) for a 2004 Nissan Maxima indicates a slow response from the downstream oxygen sensor (HO2S12). The downstream oxygen sensor is responsible for monitoring the efficiency of the catalytic converter by measuring the oxygen content in the exhaust gases after they have passed through the converter. A slow response from this sensor can lead to inaccurate readings being sent to the engine control module (ECM), which can result in poor fuel efficiency, increased emissions, and potential damage to the catalytic converter.

OBDII Code P0139 2004 Nissan Maxima - HO2S12 Slow Response
P0139 2004 Nissan Maxima Code - HO2S12 Slow Response

Common Causes of P0139 2004 Nissan Maxima

  1. Faulty downstream oxygen sensor
  2. Wiring or connector issues in the oxygen sensor circuit
  3. Exhaust leaks near the downstream oxygen sensor
  4. Contaminated or deteriorated oxygen sensor
  5. Issues with the catalytic converter

Symptoms of P0139 2004 Nissan Maxima

  1. Check engine light illuminated on the dashboard
  2. Decreased fuel efficiency
  3. Rough idling or stalling
  4. Engine misfires
  5. Reduced engine performance

How to Fix P0139 2004 Nissan Maxima

  1. Begin by connecting a diagnostic scanner to the vehicle's OBD-II port to retrieve the specific trouble code (P0139) and confirm the issue with the downstream oxygen sensor.
  2. Inspect the wiring and connectors in the oxygen sensor circuit for any signs of damage, corrosion, or loose connections. Repair or replace any faulty components as needed.
  3. Check for exhaust leaks near the downstream oxygen sensor and repair them to ensure proper sensor operation.
  4. Replace the downstream oxygen sensor if it is determined to be faulty or contaminated. Ensure to use an OEM or high-quality replacement sensor for optimal performance.
  5. Clear the DTC from the ECM's memory using the diagnostic scanner and test drive the vehicle to ensure that the issue has been resolved.

Cost to Fix P0139 2004 Nissan Maxima

The typical repair costs for addressing a P0139 code on a 2004 Nissan Maxima can range from $150 to $400, depending on the specific cause of the issue and the cost of parts and labor in your area. This estimate includes the cost of a new downstream oxygen sensor, any necessary wiring repairs, and labor charges. It's important to note that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to obtain quotes from multiple shops to ensure a competitive price. Additionally, rates may be higher at dealerships or in metropolitan areas, while independent shops may offer more affordable options.

What does this mean?

Tech Notes for P0139 2004 Nissan Maxima

Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.

When is the Code Detected?

The P0139 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor takes more time to respond between rich and lean than the specified time.

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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 2004 Nissan Maxima Code

1. What are the common symptoms of OBDII code P0139 in a 2004 Nissan Maxima?

- Common symptoms include poor fuel economy, rough idling, and decreased engine performance.

2. What does the code P0139 for a 2004 Nissan Maxima mean?

- Code P0139 indicates a slow response from the downstream oxygen sensor (HO2S12) located after the catalytic converter.

3. What are the possible causes of the HO2S12 slow response error in a 2004 Nissan Maxima?

- Causes can include a faulty oxygen sensor, wiring issues, exhaust leaks, or a malfunctioning catalytic converter.

4. How can I diagnose the HO2S12 slow response code in my 2004 Nissan Maxima?

- Diagnose by inspecting the oxygen sensor and its wiring for damage, checking for exhaust leaks, and testing the functionality of the catalytic converter.

5. Is it safe to continue driving my 2004 Nissan Maxima with OBDII code P0139?

- While the vehicle may still be operable, it is recommended to address the issue promptly to prevent further damage to the engine or catalytic converter.

6. Can I fix the HO2S12 slow response code in my 2004 Nissan Maxima myself?

- Depending on your skill level, you may be able to replace the oxygen sensor or repair wiring issues yourself. However, more complex issues may require professional assistance.

7. How much does it cost to repair OBDII code P0139 in a 2004 Nissan Maxima?

- The cost of repair can vary depending on the exact cause of the issue. Replacing an oxygen sensor may cost between $100 to $300, while fixing a catalytic converter can be more expensive.

8. Will resetting the OBDII code P0139 in my 2004 Nissan Maxima make it go away?

- Resetting the code may temporarily clear the error, but it will likely return if the underlying issue is not addressed.

9. Can a dirty air filter cause the HO2S12 slow response code in a 2004 Nissan Maxima?

- While a dirty air filter can affect engine performance, it is not a direct cause of the P0139 code. Focus on checking the oxygen sensor, wiring, and exhaust system for issues.

10. How often should the oxygen sensors be replaced in a 2004 Nissan Maxima to prevent OBDII code P0139?

- Oxygen sensors typically last between 50,000 to 100,000 miles. It's recommended to follow the manufacturer's guidelines for sensor replacement to avoid issues like code P0139.

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