AutoCodes – Nissan – P0138 2011 Nissan Pathfinder

P0138 2011 Nissan Pathfinder Code - HO2S12 Circuit High Voltage

Quick Answer

The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection. 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 Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection.
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.

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Code Popularity 2,405

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 25, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0138 2011 Nissan Pathfinder Description

The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

OBDII Code P0138 2011 Nissan Pathfinder - HO2S12 Circuit High Voltage - AutoCodes.com — P0138 2011 Nissan Pathfinder Code - HO2S12 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0138 2011 Nissan Pathfinder?

Faulty Rear Heated Oxygen Sensor Bank 1
Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Intake air leaks
Exhaust gas leaks
Inappropriate fuel pressure
Faulty fuel injectors

How to Fix the DTC P0138 2011 Nissan Pathfinder?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0138 2011 Nissan Pathfinder code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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.