AutoCodes – Nissan – P0138 2010 Nissan Sentra

P0138 2010 Nissan Sentra 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 Sentra 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 4,630

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 Sentra 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 Sentra - HO2S12 Circuit High Voltage - AutoCodes.com — P0138 2010 Nissan Sentra Code - HO2S12 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0138 2010 Nissan Sentra?

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 Sentra?

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 Sentra 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.

Need more information about the P0138 2010 Nissan Sentra code?

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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 Sentra Code

1. What does OBDII code P0138 mean for my 2010 Nissan Sentra?

- OBDII code P0138 on a 2010 Nissan Sentra indicates a high voltage condition in the HO2S12 (Heated Oxygen Sensor 1, Bank 1 Sensor 2) circuit.

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

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

3. What are the possible causes of OBDII code P0138 on a 2010 Nissan Sentra?

- Potential causes of code P0138 in a 2010 Nissan Sentra include a faulty oxygen sensor, damaged wiring or connectors in the sensor circuit, exhaust leaks, or issues with the engine's air-fuel mixture.

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

- To diagnose code P0138 on a 2010 Nissan Sentra, you can use an OBDII scanner to retrieve the code and inspect the HO2S12 sensor, wiring, and related components for any visible damage or issues.

5. Can I still drive my 2010 Nissan Sentra with OBDII code P0138?

- It is not recommended to drive your 2010 Nissan Sentra with an active P0138 code, as it can lead to decreased fuel efficiency and potential engine performance issues.

6. How can I repair OBDII code P0138 on my 2010 Nissan Sentra?

- Repairing code P0138 on a 2010 Nissan Sentra may involve replacing the HO2S12 sensor, repairing damaged wiring or connectors, fixing exhaust leaks, or addressing any issues with the air-fuel mixture.

7. Is it necessary to reset the OBDII code P0138 after making repairs on my 2010 Nissan Sentra?

- Yes, it is advisable to reset the OBDII code P0138 after performing repairs on your 2010 Nissan Sentra to clear the error code and see if the issue has been successfully resolved.

8. Can a DIY enthusiast fix OBDII code P0138 on a 2010 Nissan Sentra?

- Depending on their skill level, a DIY enthusiast may be able to fix code P0138 on a 2010 Nissan Sentra by following repair guides and using the necessary tools and replacement parts.

9. What are the consequences of ignoring OBDII code P0138 on a 2010 Nissan Sentra?

- Ignoring OBDII code P0138 on a 2010 Nissan Sentra can lead to reduced fuel efficiency, potential damage to the catalytic converter, and further engine performance issues if left unresolved.

10. How long does it typically take to repair OBDII code P0138 on a 2010 Nissan Sentra?

- The time required to repair code P0138 on a 2010 Nissan Sentra varies based on the specific cause of the issue and the individual's repair experience, but it can usually be resolved in a few hours to a day.