AutoCodes – Nissan – P0138 2010 Nissan Altima Sedan

P0138 2010 Nissan Altima Sedan 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 2010 Nissan Altima Sedan 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 5,678

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 Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0138 2010 Nissan Altima Sedan 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 2010 Nissan Altima Sedan - HO2S12 Circuit High Voltage - AutoCodes.com — P0138 2010 Nissan Altima Sedan Code - HO2S12 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0138 2010 Nissan Altima Sedan?

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 2010 Nissan Altima Sedan?

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 2010 Nissan Altima Sedan 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 2010 Nissan Altima Sedan Code

1. What does OBDII code P0138 for a 2010 Nissan Altima Sedan indicate?

The code P0138 on a 2010 Nissan Altima Sedan specifically refers to a fault in the HO2S12 (Heated Oxygen Sensor 1 Bank 1 Sensor 2) circuit, indicating high voltage.

2. What are the common symptoms of OBDII code P0138 on a 2010 Nissan Altima?

Common symptoms of code P0138 in a 2010 Nissan Altima Sedan may include poor fuel economy, rough idling, engine misfires, and the illumination of the Check Engine Light.

3. What are the potential causes of the HO2S12 Circuit High Voltage code on a 2010 Nissan Altima?

Common causes of the P0138 code in a 2010 Nissan Altima Sedan include a faulty oxygen sensor, damaged wiring or connectors in the sensor circuit, exhaust leaks, or issues with the engine's fuel management system.

4. How can I diagnose the OBDII code P0138 on my 2010 Nissan Altima Sedan?

To diagnose the P0138 code on a 2010 Nissan Altima Sedan, you may need to use an OBDII scanner to retrieve the code and then inspect the oxygen sensor, wiring, and connectors for any visible damage or issues.

5. Can I still drive my 2010 Nissan Altima Sedan with the P0138 code?

While it may be possible to drive your 2010 Nissan Altima Sedan with the P0138 code, it is recommended to address the issue promptly to prevent potential damage to the engine and ensure optimal performance.

6. How do I repair the HO2S12 Circuit High Voltage code on my 2010 Nissan Altima?

Repairing the P0138 code on a 2010 Nissan Altima Sedan typically involves replacing the faulty oxygen sensor, repairing any damaged wiring or connectors, fixing exhaust leaks, or addressing issues with the fuel management system.

7. Are there any DIY tips for fixing the P0138 code on a 2010 Nissan Altima Sedan?

While some aspects of diagnosing and repairing the P0138 code may be DIY-friendly, it is recommended to consult a professional mechanic for accurate diagnosis and proper repair to ensure the issue is resolved effectively.

8. How much does it cost to fix the OBDII code P0138 on a 2010 Nissan Altima Sedan?

The cost of fixing the P0138 code on a 2010 Nissan Altima Sedan can vary depending on the exact cause of the issue, but it may range from a few hundred dollars to over a thousand dollars, including parts and labor.

9. Will resetting the Check Engine Light clear the P0138 code on my 2010 Nissan Altima Sedan?

Simply resetting the Check Engine Light may temporarily clear the P0138 code, but if the underlying issue causing the code is not addressed, the light is likely to reappear once the problem is detected again.

10. How can I prevent the OBDII code P0138 from recurring on my 2010 Nissan Altima Sedan?

To prevent the P0138 code from recurring on your 2010 Nissan Altima Sedan, it is essential to perform regular maintenance, address any engine-related issues promptly, and ensure the oxygen sensors and related components are in good working condition.