Engine-Codes.com
Engine-Codes – Nissan – P0138 2008 Nissan Sentra

P0138 2008 Nissan Sentra Code - HO2S12 Circuit High Voltage

Quick Answer

The P0138 diagnostic trouble code (DTC) for a 2008 Nissan Sentra indicates that the oxygen sensor (O2 sensor) located in bank 1 sensor 2 is reporting a high voltage condition. Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor. 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 2008 Nissan Sentra indicates HO2S12 Circuit High Voltage.
Common causes
Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor.
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 16, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0138 2008 Nissan Sentra Description

The P0138 diagnostic trouble code (DTC) for a 2008 Nissan Sentra indicates that the oxygen sensor (O2 sensor) located in bank 1 sensor 2 is reporting a high voltage condition. The O2 sensor is responsible for measuring the oxygen content in the exhaust gases and providing feedback to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion. When the voltage from the sensor is higher than expected, it can lead to issues with fuel efficiency, emissions, and overall engine performance.

OBDII Code P0138 2008 Nissan Sentra - HO2S12 Circuit High Voltage
P0138 2008 Nissan Sentra Code - HO2S12 Circuit High Voltage

Common Causes of P0138 2008 Nissan Sentra

  1. Faulty oxygen sensor
  2. Wiring or connector issues
  3. Exhaust leaks near the sensor
  4. ECM malfunction
  5. Engine running rich

Symptoms of P0138 2008 Nissan Sentra

  1. Decreased fuel efficiency
  2. Check Engine Light illuminated
  3. Rough idling or stalling
  4. Poor acceleration
  5. Increased emissions

How to Fix P0138 2008 Nissan Sentra

  1. Begin by locating the bank 1 sensor 2 oxygen sensor in the exhaust system.
  2. Inspect the wiring and connectors for any damage or corrosion.
  3. Test the oxygen sensor using a multimeter to check for proper voltage output.
  4. Replace the oxygen sensor if it is determined to be faulty.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0138 2008 Nissan Sentra

The cost of repairing a P0138 code on a 2008 Nissan Sentra can vary depending on the specific cause of the issue. Typically, the price of a new oxygen sensor ranges from $50 to $200, depending on the brand and quality. Labor costs at an auto repair shop can range from $100 to $300, depending on the shop's hourly rate and the complexity of the repair. Overall, the total cost of resolving this issue could range from $150 to $500. It's important to note that these are rough estimates, and actual costs may vary based on location and other factors. It's recommended to consult with a qualified mechanic for a more accurate cost estimate.

What does this mean?

Tech Notes for P0138 2008 Nissan Sentra

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.

Need more information about the P0138 2008 Nissan Sentra code?

Need more information on how to fix the P0138 2008 Nissan Sentra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0138 2008 Nissan Sentra code diagnosed by a professional: Find a repair shop in your area

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 2008 Nissan Sentra Code

1. What does the OBDII code P0138 mean for a 2008 Nissan Sentra?

The code P0138 for a 2008 Nissan Sentra indicates a high voltage condition in the HO2S12 (Heated Oxygen Sensor Bank 1 Sensor 2) circuit.

2. What are common symptoms of OBDII code P0138 in a 2008 Nissan Sentra?

Common symptoms of code P0138 in a 2008 Nissan Sentra may include poor fuel economy, rough idling, engine hesitation, and the illumination of the check engine light.

3. What are possible causes of OBDII code P0138 in a 2008 Nissan Sentra?

Possible causes of code P0138 in a 2008 Nissan Sentra include a faulty HO2S12 sensor, wiring issues in the sensor circuit, exhaust leaks, or a malfunctioning engine control module (ECM).

4. How can I diagnose the OBDII code P0138 in my 2008 Nissan Sentra?

To diagnose code P0138 in a 2008 Nissan Sentra, you can perform a visual inspection of the sensor and its wiring, test the sensor's voltage output, check for exhaust leaks, and use a scan tool to monitor sensor data.

5. What is the recommended repair for OBDII code P0138 in a 2008 Nissan Sentra?

The recommended repair for code P0138 in a 2008 Nissan Sentra may involve replacing the HO2S12 sensor, repairing any damaged wiring, fixing exhaust leaks, or reprogramming the ECM if necessary.

6. Can I drive my 2008 Nissan Sentra with OBDII code P0138?

It is not recommended to drive a 2008 Nissan Sentra with OBDII code P0138 for an extended period as it can affect the vehicle's performance and fuel efficiency. It's best to address the issue promptly.

7. How much does it typically cost to fix OBDII code P0138 in a 2008 Nissan Sentra?

The cost to fix OBDII code P0138 in a 2008 Nissan Sentra can vary depending on the root cause of the issue. Replacing the HO2S12 sensor may cost between $100 to $200, while addressing wiring or ECM problems can be more expensive.

8. Can a DIY enthusiast repair OBDII code P0138 in a 2008 Nissan Sentra?

DIY enthusiasts with the necessary tools and knowledge of automotive repair may be able to address OBDII code P0138 in a 2008 Nissan Sentra. However, it's important to diagnose the issue accurately before attempting any repairs.

9. How soon should I address OBDII code P0138 in my 2008 Nissan Sentra?

It is recommended to address OBDII code P0138 in a 2008 Nissan Sentra as soon as possible to prevent potential damage to the vehicle's engine and emission control system, as well as to ensure optimal performance.

10. Will resetting the OBDII code P0138 in my 2008 Nissan Sentra make it go away permanently?

Resetting the OBDII code P0138 in a 2008 Nissan Sentra may temporarily turn off the check engine light, but if the underlying issue is not resolved, the code is likely to reappear. It's essential to diagnose and fix the root cause of the problem.

Discuss the causes and fixes for P0138 2008 Nissan Sentra OBDII Code

Submit a New Comment

Code P0138 2008 Nissan Sentra comments

No comments found for this page.