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Engine-Codes – Nissan – P0138 2003 Nissan Altima Sedan

P0138 2003 Nissan Altima Sedan Code - HO2S12 Circuit High Voltage

Quick Answer

The P0138 diagnostic trouble code (DTC) in a 2003 Nissan Altima Sedan indicates that the oxygen sensor (O2) located in bank 1 sensor 2 is registering a high voltage condition. Common causes include Faulty 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
P0138 2003 Nissan Altima Sedan indicates HO2S12 Circuit High Voltage.
Common causes
Common causes include Faulty 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 13, 2024
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Code P0138 2003 Nissan Altima Sedan Description

The P0138 diagnostic trouble code (DTC) in a 2003 Nissan Altima Sedan indicates that the oxygen sensor (O2) located in bank 1 sensor 2 is registering a high voltage condition. This sensor, also known as the downstream oxygen sensor, plays a crucial role in monitoring the oxygen levels in the exhaust gases after they have passed through the catalytic converter. The O2 sensor provides feedback to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion efficiency.

OBDII Code P0138 2003 Nissan Altima Sedan - HO2S12 Circuit High Voltage
P0138 2003 Nissan Altima Sedan Code - HO2S12 Circuit High Voltage

Common Causes of P0138 2003 Nissan Altima Sedan

  1. Faulty oxygen sensor
  2. Wiring or connector issues
  3. Exhaust leaks near the sensor
  4. Engine running rich due to a fuel system problem
  5. ECM software or hardware malfunction

Symptoms of P0138 2003 Nissan Altima Sedan

  1. Decreased fuel efficiency
  2. Check Engine Light illuminated
  3. Rough idling or engine misfires
  4. Poor acceleration or hesitation
  5. Increased emissions

How to Fix P0138 2003 Nissan Altima Sedan

  1. Diagnose the issue by using a scan tool to monitor the O2 sensor's voltage readings.
  2. Inspect the wiring and connectors for any damage or corrosion. Repair or replace as needed.
  3. Check for exhaust leaks near the sensor and repair if necessary.
  4. Test the oxygen sensor using a multimeter to verify its functionality. Replace if faulty.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0138 2003 Nissan Altima Sedan

The typical repair costs for addressing a P0138 code in a 2003 Nissan Altima Sedan can range from $150 to $400, depending on the specific cause of the issue and the cost of parts and labor. It's important to note that diagnosis time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate. Additionally, factors such as the vehicle's make and model, as well as the engine type, can also impact the overall repair costs.

What does this mean?

Tech Notes for P0138 2003 Nissan Altima Sedan

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

When is the Code Detected?

The P0138 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor signal voltage remains excessively high for an extended period of 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 P0138 2003 Nissan Altima Sedan Code

1. What are the common symptoms of OBDII code P0138 on a 2003 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 P0138 "HO2S12 Circuit High Voltage" indicate in a 2003 Nissan Altima Sedan?

- This code indicates that the oxygen sensor (HO2S12) located after the catalytic converter is detecting a high voltage condition.

3. What are the possible causes of OBDII code P0138 on a 2003 Nissan Altima Sedan?

- Possible causes include a faulty oxygen sensor (HO2S12), wiring issues in the sensor circuit, a vacuum leak, exhaust system leaks, or a malfunctioning catalytic converter.

4. How can I diagnose the cause of OBDII code P0138 on my 2003 Nissan Altima Sedan?

- To diagnose the issue, you can use an OBDII scanner to read the code, visually inspect the oxygen sensor and its wiring, check for exhaust leaks, and perform voltage tests on the sensor.

5. Can I drive my 2003 Nissan Altima Sedan with OBDII code P0138?

- It is not recommended to drive the vehicle with a P0138 code for an extended period as it can lead to decreased fuel efficiency and potentially cause damage to the catalytic converter.

6. How can I repair OBDII code P0138 on a 2003 Nissan Altima Sedan?

- Repair options include replacing the oxygen sensor (HO2S12), repairing any damaged wiring in the sensor circuit, fixing exhaust leaks, and addressing any other underlying issues causing the high voltage condition.

7. Will resetting the Check Engine light resolve OBDII code P0138 on my 2003 Nissan Altima Sedan?

- Simply resetting the Check Engine light will not fix the underlying issue causing the P0138 code. It is important to diagnose and repair the root cause of the problem.

8. How much does it cost to repair OBDII code P0138 on a 2003 Nissan Altima Sedan?

- The cost of repairing P0138 can vary depending on the specific cause of the issue, but it may involve replacing the oxygen sensor, which can range from $100 to $300 including parts and labor.

9. Can a DIY enthusiast fix OBDII code P0138 on a 2003 Nissan Altima Sedan?

- Depending on the DIY enthusiast's skill level, it is possible to address some of the common causes of P0138, such as replacing the oxygen sensor or repairing simple wiring issues. However, more complex problems may require professional assistance.

10. How often does OBDII code P0138 occur in a 2003 Nissan Altima Sedan?

- The occurrence of P0138 can vary, but it is a relatively common code related to oxygen sensor malfunctions in vehicles, including the 2003 Nissan Altima Sedan.

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