Engine-CodesNissan – P0138 2006 Nissan Sentra

P0138 2006 Nissan Sentra Code - HO2S12 Circuit High Voltage

Quick Answer

The P0138 diagnostic trouble code (DTC) for a 2006 Nissan Sentra refers to an issue with the HO2S12 sensor circuit, specifically indicating high voltage. Common causes include Faulty HO2S12 sensor, Wiring issues such as shorts or opens, 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 2006 Nissan Sentra indicates HO2S12 Circuit High Voltage.
Common causes
Common causes include Faulty HO2S12 sensor, Wiring issues such as shorts or opens, 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.
Table of contents Created and updated by William Orellana on Sep 13, 2024
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Code P0138 2006 Nissan Sentra Description

The P0138 diagnostic trouble code (DTC) for a 2006 Nissan Sentra refers to an issue with the HO2S12 sensor circuit, specifically indicating high voltage. The HO2S12 sensor, also known as the downstream oxygen sensor, is responsible for monitoring the oxygen levels in the exhaust gases after they have passed through the catalytic converter. This information is crucial for the engine control module (ECM) to adjust the air-fuel mixture to optimize combustion and reduce emissions.

OBDII Code P0138 2006 Nissan Sentra - HO2S12 Circuit High Voltage
P0138 2006 Nissan Sentra Code - HO2S12 Circuit High Voltage

Common Causes of P0138 2006 Nissan Sentra

  1. Faulty HO2S12 sensor
  2. Wiring issues such as shorts or opens
  3. Exhaust leaks near the sensor
  4. Engine running rich
  5. ECM malfunction

Symptoms of P0138 2006 Nissan Sentra

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

How to Fix P0138 2006 Nissan Sentra

  1. Begin by diagnosing the issue using a scan tool to confirm the P0138 code and identify the specific problem.
  2. Inspect the wiring harness and connectors for any damage or corrosion. Repair or replace as necessary.
  3. Check for exhaust leaks near the HO2S12 sensor and repair them to ensure accurate readings.
  4. Test the HO2S12 sensor using a multimeter to determine if it is functioning properly. Replace if needed.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0138 2006 Nissan Sentra

The cost of repairing a P0138 code on a 2006 Nissan Sentra can vary depending on the specific cause of the issue. In general, replacing an oxygen sensor can cost between $100 and $300, including parts and labor. However, if additional repairs or diagnostics are needed, the total cost could be higher. It's important to consult with a qualified mechanic or auto repair shop for an accurate estimate based on your vehicle's specific needs. Keep in mind that labor rates can vary, so it's advisable to check local rates for a more precise estimate.

Tech Notes for P0138 2006 Nissan Sentra

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 2006 Nissan Sentra Code

1. What does the OBDII code P0138 on a 2006 Nissan Sentra mean?

- The code P0138 indicates a high voltage condition in the HO2S12 (Heated Oxygen Sensor Bank 1 Sensor 2) circuit of a 2006 Nissan Sentra.

2. What are the common symptoms of a P0138 code in a 2006 Nissan Sentra?

- Common symptoms include poor fuel economy, rough idling, engine misfires, and the illumination of the check engine light.

3. What are the possible causes of a P0138 code on a 2006 Nissan Sentra?

- The main causes of a P0138 code include a faulty HO2S12 sensor, wiring issues in the sensor circuit, exhaust leaks, or a problem with the engine's fuel system.

4. How can I diagnose a P0138 code on my 2006 Nissan Sentra?

- Diagnosis involves using an OBDII scanner to read the code, checking the wiring and connections to the HO2S12 sensor, and testing the sensor's voltage output.

5. Can I continue driving my 2006 Nissan Sentra with a P0138 code?

- It is generally not recommended to drive with a P0138 code as it can lead to decreased fuel efficiency and potential damage to the engine over time.

6. How do I repair a P0138 code on my 2006 Nissan Sentra?

- Repair options include replacing the HO2S12 sensor, repairing any damaged wiring or connections, fixing exhaust leaks, and addressing any fuel system issues.

7. Is it possible to reset the check engine light after fixing a P0138 code on a 2006 Nissan Sentra?

- Yes, you can reset the check engine light using an OBDII scanner after the issue causing the P0138 code has been resolved.

8. How much does it typically cost to fix a P0138 code on a 2006 Nissan Sentra?

- The cost of fixing a P0138 code can vary depending on the exact cause, but it may range from $100 to $300 for parts and labor.

9. Can a P0138 code on a 2006 Nissan Sentra cause emissions test failure?

- Yes, a P0138 code can cause emissions test failure due to the impact on the vehicle's emissions control system.

10. How often does a P0138 code occur in a 2006 Nissan Sentra?

- The occurrence of a P0138 code can vary, but it is not uncommon in older vehicles like the 2006 Nissan Sentra with high mileage or poor maintenance.

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