AutoCodes – Nissan – P0138 2011 Nissan Sentra

P0138 2011 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 2011 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 3,329

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

What does this mean?

What are the Possible Causes of the DTC P0138 2011 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 2011 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 2011 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 2011 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 2011 Nissan Sentra Code

1. What does the OBDII code P0138 for a 2011 Nissan Sentra indicate?

The code P0138 on a 2011 Nissan Sentra refers to a fault with the HO2S12 (Heated Oxygen Sensor Bank 1 Sensor 2) circuit showing high voltage.

2. What are the common symptoms of OBDII code P0138 on a 2011 Nissan Sentra?

Common symptoms of code P0138 on a 2011 Nissan Sentra include poor fuel economy, rough idling, stalling, and the illumination of the check engine light.

3. What are the potential causes of the HO2S12 circuit high voltage error on a 2011 Nissan Sentra?

Potential causes of the P0138 code on a 2011 Nissan Sentra can include a faulty oxygen sensor, wiring issues, a vacuum leak, or a problem with the engine's fuel system.

4. How can I diagnose the HO2S12 circuit high voltage issue on my 2011 Nissan Sentra?

To diagnose the P0138 code on a 2011 Nissan Sentra, you can use an OBDII scanner to read the code, visually inspect the wiring and connectors, test the oxygen sensor's voltage, and check for any vacuum leaks.

5. Can a dirty or contaminated oxygen sensor cause the P0138 code on a 2011 Nissan Sentra?

Yes, a dirty or contaminated oxygen sensor can potentially cause the P0138 code on a 2011 Nissan Sentra as it may not function properly and lead to erroneous high voltage readings.

6. What are some repair tips for fixing the HO2S12 circuit high voltage error on a 2011 Nissan Sentra?

Repair tips for addressing the P0138 code on a 2011 Nissan Sentra include cleaning or replacing the oxygen sensor, repairing any damaged wiring, fixing vacuum leaks, and ensuring proper fuel system operation.

7. Is it safe to continue driving my 2011 Nissan Sentra with the P0138 code illuminated?

It is not recommended to continue driving your 2011 Nissan Sentra with the P0138 code illuminated as it can lead to decreased fuel efficiency and potential engine performance issues.

8. Can I reset the check engine light after fixing the HO2S12 circuit high voltage problem on my 2011 Nissan Sentra?

Yes, after addressing the underlying cause of the P0138 code on your 2011 Nissan Sentra, you can reset the check engine light using an OBDII scanner to clear the stored error code.

9. How much does it typically cost to repair the P0138 code on a 2011 Nissan Sentra at a mechanic or dealership?

The cost of repairing the P0138 code on a 2011 Nissan Sentra can vary depending on the exact cause of the issue, but it may range from $100 to $300 for parts and labor at a mechanic or dealership.

10. Are there any recalls or technical service bulletins related to the OBDII code P0138 on a 2011 Nissan Sentra?

Check with your local Nissan dealership or visit the National Highway Traffic Safety Administration (NHTSA) website to see if there are any recalls or technical service bulletins related to the P0138 code on a 2011 Nissan Sentra.