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P0138 2011 Nissan Pathfinder Code - HO2S12 Circuit High Voltage

Quick Answer

The diagnostic trouble code P0138 in a 2011 Nissan Pathfinder indicates an issue with the HO2S12 (Heated Oxygen Sensor 1 Bank 1 Sensor 2) circuit, specifically that the voltage is reading higher than normal. Common causes include Faulty HO2S12 sensor, Wiring issues such as shorts or open circuits, Engine control module malfunction. 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 2011 Nissan Pathfinder indicates HO2S12 Circuit High Voltage.
Common causes
Common causes include Faulty HO2S12 sensor, Wiring issues such as shorts or open circuits, Engine control module malfunction.
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 10, 2024
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Code P0138 2011 Nissan Pathfinder Description

The diagnostic trouble code P0138 in a 2011 Nissan Pathfinder indicates an issue with the HO2S12 (Heated Oxygen Sensor 1 Bank 1 Sensor 2) circuit, specifically that the voltage is reading higher than normal. The HO2S12 sensor is responsible for measuring the oxygen content in the exhaust gases after they have passed through the catalytic converter. This information is crucial for the engine control module to adjust fuel delivery and optimize combustion efficiency.

OBDII Code P0138 2011 Nissan Pathfinder - HO2S12 Circuit High Voltage
P0138 2011 Nissan Pathfinder Code - HO2S12 Circuit High Voltage

Common Causes of P0138 2011 Nissan Pathfinder

  1. Faulty HO2S12 sensor
  2. Wiring issues such as shorts or open circuits
  3. Engine control module malfunction
  4. Exhaust leaks upstream of the sensor
  5. Fuel system issues such as a clogged fuel filter or injector

Symptoms of P0138 2011 Nissan Pathfinder

  1. Check Engine Light illuminated on the dashboard
  2. Reduced fuel efficiency
  3. Rough idling or stalling
  4. Engine hesitation or surging
  5. Increased emissions

How to Fix P0138 2011 Nissan Pathfinder

  1. Begin by conducting a visual inspection of the HO2S12 sensor and its wiring harness for any obvious signs of damage.
  2. Use a multimeter to test the sensor's voltage output and compare it to specifications provided by the manufacturer.
  3. If the sensor voltage is out of range, replace the HO2S12 sensor with a new one.
  4. Check the wiring harness for continuity and repair any damaged wires if necessary.
  5. Clear the diagnostic trouble codes from the engine control module and perform a test drive to verify that the issue has been resolved.

Cost to Fix P0138 2011 Nissan Pathfinder

The cost of repairing a P0138 trouble code in a 2011 Nissan Pathfinder can vary depending on the specific cause of the issue. Typically, the price of a new HO2S12 sensor ranges from $50 to $200, while labor costs can range from $100 to $300. Overall, the total repair cost for this issue may range from $150 to $500. It's important to note that diagnostic time and labor rates can vary, so it's recommended to consult with a local auto repair shop for a more accurate estimate.

What does this mean?

Tech Notes for P0138 2011 Nissan Pathfinder

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 2011 Nissan Pathfinder Code

1. What does the OBDII code P0138 for a 2011 Nissan Pathfinder mean?

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

2. What are the common symptoms of the P0138 code in a 2011 Nissan Pathfinder?

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

3. What are the possible causes of the P0138 code in a 2011 Nissan Pathfinder?

- The code P0138 can be triggered by a faulty HO2S12 sensor, wiring issues, exhaust leaks, engine misfires, or a malfunctioning engine control module (ECM).

4. How do I diagnose the P0138 code in my 2011 Nissan Pathfinder?

- Diagnosing the P0138 code involves checking the HO2S12 sensor's voltage output, inspecting the sensor and its wiring for damage, and verifying the integrity of the exhaust system.

5. Can I drive my 2011 Nissan Pathfinder with the P0138 code?

- It is not recommended to drive your vehicle with the P0138 code unresolved, as it can lead to poor engine performance and potential damage to the catalytic converter.

6. How can I repair the P0138 code in my 2011 Nissan Pathfinder?

- Repair options include replacing the HO2S12 sensor, repairing damaged wiring or connectors, fixing exhaust leaks, addressing engine misfires, or reprogramming the ECM.

7. Will resetting the check engine light fix the P0138 code in my 2011 Nissan Pathfinder?

- Simply resetting the check engine light will not fix the underlying issue causing the P0138 code. Proper diagnosis and repair are necessary to resolve the problem.

8. How much does it cost to fix the P0138 code in a 2011 Nissan Pathfinder?

- The cost of fixing the P0138 code can vary depending on the root cause of the issue. Costs may include parts such as a new sensor, labor for diagnostics, and potential repairs.

9. How long does it take to repair the P0138 code in a 2011 Nissan Pathfinder?

- The repair time for the P0138 code can vary based on the diagnostic process, availability of parts, and complexity of the repair. It may take a few hours to a full day.

10. Can I prevent the P0138 code from appearing again in my 2011 Nissan Pathfinder?

- To prevent the recurrence of the P0138 code, ensure regular maintenance of your vehicle, address any engine issues promptly, and use quality fuel to avoid potential sensor damage.

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