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P0139 2002 Nissan Altima Sedan Code - HO2S12 Slow Response

Quick Answer

The diagnostic trouble code P0139 for a 2002 Nissan Altima Sedan indicates a slow response from the downstream oxygen sensor, also known as the HO2S12 sensor. Common causes include Faulty downstream oxygen sensor, Wiring or connector issues, Exhaust leaks near the 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 2002 Nissan Altima Sedan indicates HO2S12 Slow Response.
Common causes
Common causes include Faulty downstream oxygen sensor, Wiring or connector issues, Exhaust leaks near the 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 08, 2024
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Code P0139 2002 Nissan Altima Sedan Description

The diagnostic trouble code P0139 for a 2002 Nissan Altima Sedan indicates a slow response from the downstream oxygen sensor, also known as the HO2S12 sensor. This sensor is responsible for monitoring the oxygen levels in the exhaust gases after they have passed through the catalytic converter. The data from this sensor is crucial for the engine control module (ECM) to adjust the air-fuel mixture to optimize combustion and reduce emissions.

OBDII Code P0139 2002 Nissan Altima Sedan - HO2S12 Slow Response
P0139 2002 Nissan Altima Sedan Code - HO2S12 Slow Response

Common Causes of P0139 2002 Nissan Altima Sedan

  1. Faulty downstream oxygen sensor
  2. Wiring or connector issues
  3. Exhaust leaks near the sensor
  4. Problems with the catalytic converter
  5. Contaminated sensor due to oil or coolant leaks

Symptoms of P0139 2002 Nissan Altima Sedan

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Hesitation during acceleration
  4. Check Engine Light illuminated
  5. Increased emissions

How to Fix P0139 2002 Nissan Altima Sedan

  1. Diagnose the issue by connecting a scan tool to retrieve the specific trouble code and monitor the oxygen sensor's data.
  2. Inspect the wiring and connectors for any signs of damage or corrosion, repairing or replacing as necessary.
  3. Check for exhaust leaks near the sensor and repair them to ensure accurate readings.
  4. Replace the downstream oxygen sensor if it is determined to be faulty or contaminated.
  5. Clear the trouble code and perform a test drive to confirm that the issue has been resolved.

Cost to Fix P0139 2002 Nissan Altima Sedan

The typical repair costs for resolving a slow response from the downstream oxygen sensor on a 2002 Nissan Altima Sedan can range from $150 to $400, including parts and labor. However, it's important to note that the specific diagnosis time and labor rates at auto repair shops can vary based on various factors. Rates in metropolitan areas or at dealerships may be higher, while independent shops often charge less. It's advisable to check with local shops for a more accurate estimate based on your location and vehicle specifics.

What does this mean?

Tech Notes for P0139 2002 Nissan Altima Sedan

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 2002 Nissan Altima Sedan Code

1. What are the common symptoms of OBDII code P0139 in a 2002 Nissan Altima Sedan?

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

2. What does the OBDII code P0139 "HO2S12 Slow Response" indicate in a 2002 Nissan Altima Sedan?

- This code indicates that the downstream oxygen sensor (HO2S12) in bank 1 is not responding quickly enough to changes in the oxygen level in the exhaust gas.

3. What are the possible causes of the P0139 code in a 2002 Nissan Altima Sedan?

- Common causes include a faulty oxygen sensor, wiring or connector issues, exhaust leaks, engine misfires, or a malfunctioning catalytic converter.

4. How can I diagnose the P0139 code in my 2002 Nissan Altima Sedan?

- Diagnostic steps include checking the oxygen sensor's wiring and connections, inspecting for exhaust leaks, testing the sensor's response rate, and verifying the functionality of related components.

5. Can I drive my 2002 Nissan Altima Sedan with the P0139 code?

- It is generally safe to drive the vehicle with this code, but it is recommended to address the issue promptly to prevent potential damage to the catalytic converter and ensure optimal engine performance.

6. How can I repair the P0139 code in my 2002 Nissan Altima Sedan?

- Repair options may include replacing the downstream oxygen sensor, repairing damaged wiring or connectors, fixing exhaust leaks, addressing engine misfires, or replacing a faulty catalytic converter if necessary.

7. Will resetting the Check Engine Light resolve the P0139 code in my 2002 Nissan Altima Sedan?

- Resetting the Check Engine Light may temporarily turn it off, but if the underlying issue causing the P0139 code is not addressed, the light is likely to come back on as the vehicle's onboard diagnostic system detects the problem.

8. How much does it cost to fix the P0139 code in a 2002 Nissan Altima Sedan?

- The cost of fixing the P0139 code can vary depending on the specific cause of the issue. It may range from a simple sensor replacement costing around $100 to more extensive repairs involving the catalytic converter, which can be several hundred dollars.

9. Can a DIY enthusiast repair the P0139 code in a 2002 Nissan Altima Sedan?

- Depending on the root cause of the issue, some DIY enthusiasts with the necessary tools and skills may be able to replace the oxygen sensor or address wiring problems. However, more complex issues may require professional diagnosis and repair.

10. How long does it take to repair the P0139 code in a 2002 Nissan Altima Sedan?

- The repair time can vary based on the specific problem and the expertise of the individual performing the repair. Simple fixes like sensor replacement may take an hour or two, while more involved repairs could take longer and may require multiple steps.

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