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P0138 Dodge Code - O2 Sensor 1/2 Circuit High

Quick Answer

The P0138 diagnostic trouble code (DTC) for Dodge vehicles specifically refers to an issue with the O2 sensor 1/2 circuit being detected as high. Common causes include Faulty O2 sensor, Wiring or connector issues in the O2 sensor circuit, Exhaust leaks near the O2 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 Dodge indicates O2 Sensor 1/2 Circuit High.
Common causes
Common causes include Faulty O2 sensor, Wiring or connector issues in the O2 sensor circuit, Exhaust leaks near the O2 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 09, 2024
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Code P0138 Dodge Description

The P0138 diagnostic trouble code (DTC) for Dodge vehicles specifically refers to an issue with the O2 sensor 1/2 circuit being detected as high. The O2 sensor, also known as the oxygen sensor, plays a crucial role in monitoring the oxygen levels in the exhaust gases and providing feedback to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion. In this case, the O2 sensor 1/2 refers to the upstream sensor located before the catalytic converter.

OBDII Code P0138 Dodge - O2 Sensor 1/2 Circuit High
P0138 Dodge Code - O2 Sensor 1/2 Circuit High

Common Causes of P0138 Dodge

  1. Faulty O2 sensor
  2. Wiring or connector issues in the O2 sensor circuit
  3. Exhaust leaks near the O2 sensor
  4. Engine running rich or lean due to other issues
  5. ECM software or hardware problems

Symptoms of P0138 Dodge

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

How to Fix P0138 Dodge

  1. Diagnose the issue by connecting a scan tool to read the DTC and monitor the O2 sensor's voltage readings.
  2. Inspect the O2 sensor, wiring, and connectors for any visible damage or corrosion. Replace any damaged components.
  3. Check for exhaust leaks near the O2 sensor and repair as necessary.
  4. Clear the DTC and reset the ECM to monitor the O2 sensor's performance after repairs are completed.
  5. Test drive the vehicle to ensure that the issue has been resolved and the Check Engine Light does not reappear.

Cost to Fix P0138 Dodge

The typical repair costs for addressing a P0138 O2 Sensor 1/2 Circuit High code can vary depending on the specific cause of the issue and the labor rates in your area. Generally, replacing an O2 sensor can cost between $100 and $200 for the part, with additional labor costs ranging from $80 to $150 per hour. Keep in mind that additional diagnostic time may be needed to pinpoint the exact cause of the problem, so it's advisable to consult with a professional mechanic for a more accurate cost estimate.

What does this mean?

Tech Notes for P0138 Dodge

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



There is a Factory Service Bulletin for following Dodge models:

2005-2006 Dodge Magnum

2005-2006 Dodge Charger

Dodge Factory Service Bulletin OBDII Code P0138











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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.

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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 Dodge Code

1. What are the common symptoms of OBDII code P0138 in a Dodge, indicating O2 Sensor 1/2 Circuit High?

The common symptoms include poor fuel economy, rough idling, engine misfires, and the illumination of the Check Engine light.

2. What are the possible causes of OBDII code P0138 in a Dodge related to the O2 Sensor 1/2 Circuit High?

Potential causes include a faulty oxygen sensor, damaged wiring or connectors, exhaust leaks, or an issue with the engine's air-fuel mixture.

3. How can I diagnose the O2 Sensor 1/2 Circuit High issue causing OBDII code P0138 in my Dodge?

You can use an OBDII scanner to read the error code, visually inspect the oxygen sensor and its wiring, perform a voltage test, and check for any exhaust leaks.

4. Can a dirty or contaminated O2 sensor cause the OBDII code P0138 in a Dodge?

Yes, a dirty or contaminated oxygen sensor can lead to inaccurate readings and trigger the O2 Sensor 1/2 Circuit High code.

5. Is it safe to continue driving my Dodge with the OBDII code P0138 related to the O2 Sensor 1/2 Circuit High?

It is not recommended to drive your vehicle for an extended period with this issue, as it can lead to further damage and decrease fuel efficiency.

6. How can I repair the O2 Sensor 1/2 Circuit High problem causing OBDII code P0138 in my Dodge?

Repair options may include replacing the faulty oxygen sensor, repairing damaged wiring or connectors, fixing exhaust leaks, and ensuring proper air-fuel mixture.

7. Are there any DIY tips for troubleshooting and fixing the OBDII code P0138 in a Dodge due to the O2 Sensor 1/2 Circuit High?

DIY tips include checking and cleaning the oxygen sensor, inspecting the wiring harness for damage, and performing a reset of the Check Engine light after repairs.

8. Will resetting the Check Engine light resolve the OBDII code P0138 issue related to the O2 Sensor 1/2 Circuit High in my Dodge?

Resetting the light may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear after driving the vehicle.

9. How long does it typically take to repair the O2 Sensor 1/2 Circuit High problem causing OBDII code P0138 in a Dodge?

The repair time can vary depending on the exact cause of the issue, but it may take anywhere from 30 minutes to a few hours to complete the necessary repairs.

10. Can a mechanic help me diagnose and repair the OBDII code P0138 in my Dodge related to the O2 Sensor 1/2 Circuit High?

Yes, a qualified mechanic can perform a thorough diagnostic, identify the root cause of the problem, and effectively repair the issue to resolve the O2 Sensor 1/2 Circuit High code.

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