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P0138 Saturn Code - HO2S Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The P0138 diagnostic trouble code (DTC) for a Saturn indicates an issue with the HO2S (Heated Oxygen Sensor) circuit having high voltage on Bank 1, Sensor 2. Common causes include Faulty HO2S Bank 1 Sensor 2, Damaged or corroded wiring/connectors, 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 Saturn indicates HO2S Circuit High Voltage Bank 1 Sensor 2.
Common causes
Common causes include Faulty HO2S Bank 1 Sensor 2, Damaged or corroded wiring/connectors, 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 07, 2024
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Code P0138 Saturn Description

The P0138 diagnostic trouble code (DTC) for a Saturn indicates an issue with the HO2S (Heated Oxygen Sensor) circuit having high voltage on Bank 1, Sensor 2. This sensor is responsible for monitoring the oxygen levels in the exhaust gases after they have passed through the catalytic converter. The data provided by this sensor is crucial for the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion efficiency.

OBDII Code P0138 Saturn - HO2S Circuit High Voltage Bank 1 Sensor 2
P0138 Saturn Code - HO2S Circuit High Voltage Bank 1 Sensor 2

Common Causes of P0138 Saturn

  1. Faulty HO2S Bank 1 Sensor 2
  2. Damaged or corroded wiring/connectors
  3. Exhaust leaks near the sensor
  4. Issues with the ECM
  5. Fuel system problems affecting the air-fuel mixture

Symptoms of P0138 Saturn

  1. Decreased fuel efficiency
  2. Rough idling or engine stalling
  3. Check Engine Light illuminated on the dashboard
  4. Increased emissions output
  5. Engine misfires

How to Fix P0138 Saturn

  1. Begin by diagnosing the specific cause of the high voltage reading, which may involve using a multimeter to test the sensor's output and inspecting the wiring for any damage or corrosion.
  2. If the issue lies with the sensor itself, replace the HO2S Bank 1 Sensor 2 with a new, OEM equivalent part.
  3. Repair or replace any damaged wiring or connectors in the sensor circuit.
  4. Clear the DTC from the ECM's memory using a diagnostic scan tool and monitor the sensor's output to ensure the issue has been resolved.
  5. Perform a test drive to verify that the vehicle's performance has improved and that the Check Engine Light does not reappear.

Cost to Fix P0138 Saturn

The cost of repairing a P0138 DTC on a Saturn can vary depending on the specific cause of the issue and the labor rates in your area. Typically, the price of a new HO2S Bank 1 Sensor 2 can range from $50 to $200, with additional costs for labor and diagnostic time. Overall, you can expect to pay anywhere from $150 to $400 for parts and labor at an auto repair shop. Keep in mind that rates can vary based on location, vehicle make and model, and the expertise of the technician performing the repairs. It's recommended to obtain quotes from multiple shops to ensure you get a fair price for the repair.

What does this mean?

Tech Notes for P0138 Saturn

Replacing the Rear Heated Oxygen Sensor (HO2S) Bank 1 usually takes care of the problem.

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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 Saturn Code

1. What are the common symptoms of OBDII code P0138 in a Saturn?

- Common symptoms include poor fuel economy, rough idling, engine hesitation, and an illuminated Check Engine light.

2. What does the OBDII code P0138 "HO2S Circuit High Voltage Bank 1 Sensor 2" mean for a Saturn?

- This code indicates that the oxygen sensor (O2 sensor) located downstream of the catalytic converter in Bank 1 is detecting a high voltage condition.

3. What are the possible causes of OBDII code P0138 in a Saturn?

- Possible causes include a faulty oxygen sensor, wiring issues in the sensor circuit, exhaust leaks, a malfunctioning catalytic converter, or an engine running too rich.

4. How serious is OBDII code P0138 in a Saturn?

- While the vehicle may still be drivable with this code, it can lead to decreased fuel efficiency and increased emissions. It is recommended to address this issue promptly to prevent further damage to the engine or catalytic converter.

5. Can I continue driving my Saturn with OBDII code P0138 present?

- It is generally safe to drive the vehicle with this code, but it is advisable to have it diagnosed and repaired as soon as possible to avoid potential engine performance issues.

6. How can I diagnose and repair OBDII code P0138 in my Saturn?

- Diagnosis typically involves testing the oxygen sensor, inspecting the sensor wiring, and checking for exhaust leaks. Repair may involve replacing the oxygen sensor, repairing wiring issues, or addressing other underlying causes.

7. Can a DIY enthusiast fix OBDII code P0138 in a Saturn?

- Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to address this code by replacing the oxygen sensor or fixing wiring issues. However, professional diagnosis and repair may be recommended for more complex issues.

8. Is it necessary to reset the OBDII code P0138 after making repairs in a Saturn?

- Yes, it is important to reset the code using an OBDII scanner after making any repairs to clear the Check Engine light and ensure that the issue has been resolved.

9. How much does it cost to repair OBDII code P0138 in a Saturn?

- The cost of repairing this code can vary depending on the specific cause of the issue, the labor rates in your area, and whether you choose to address the problem yourself or take it to a professional mechanic.

10. How can I prevent OBDII code P0138 from reoccurring in my Saturn?

- To prevent this code from reoccurring, it is important to address any underlying issues promptly, perform regular maintenance on your vehicle, and drive responsibly to minimize stress on the engine and emissions system.

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