Engine-CodesPontiac – P0138 Pontiac

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

Quick Answer

The P0138 diagnostic trouble code (DTC) for Pontiac vehicles indicates a high voltage condition in the oxygen sensor (O2) circuit for Bank 1 Sensor 2. Common causes include Faulty oxygen sensor, Wiring or connector issues, ECM malfunction. 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 Pontiac indicates HO2S Circuit High Voltage Bank 1 Sensor 2.
Common causes
Common causes include Faulty oxygen sensor, Wiring or connector issues, ECM malfunction.
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.
Table of contents Created and updated by William Orellana on Sep 06, 2024
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Code P0138 Pontiac Description

The P0138 diagnostic trouble code (DTC) for Pontiac vehicles indicates a high voltage condition in the oxygen sensor (O2) circuit for Bank 1 Sensor 2. This sensor is located downstream of the catalytic converter and is responsible for monitoring the oxygen content in the exhaust gases. The O2 sensor sends signals to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion. A high voltage reading from this sensor can indicate an issue with the sensor itself, the wiring, or the ECM.

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

Common Causes of P0138 Pontiac

  1. Faulty oxygen sensor
  2. Wiring or connector issues
  3. ECM malfunction
  4. Exhaust leaks
  5. Rich air-fuel mixture

Symptoms of P0138 Pontiac

  1. Decreased fuel efficiency
  2. Engine misfires or hesitation
  3. Rough idling or stalling
  4. Check Engine Light illuminated
  5. Failed emissions test

How to Fix P0138 Pontiac

  1. Diagnose the issue using an OBD-II scanner to confirm the P0138 code and pinpoint the exact cause.
  2. Inspect the wiring and connectors for any damage or corrosion, and repair or replace as needed.
  3. Test the oxygen sensor using a multimeter to determine if it is functioning correctly.
  4. Replace the Bank 1 Sensor 2 oxygen sensor if it is found to be faulty.
  5. Clear the DTC and perform a test drive to ensure the issue has been resolved.

Cost to Fix P0138 Pontiac

The cost of repairing a P0138 code can vary depending on the specific cause of the issue and the labor rates in your area. Typically, the price of a new oxygen sensor for Bank 1 Sensor 2 ranges from $50 to $200, while the labor cost for installation can be around $100 to $200. Overall, the total repair cost for addressing the HO2S Circuit High Voltage Bank 1 Sensor 2 code may range from $150 to $400, but it is advisable to get a personalized quote from a local auto repair shop for a more accurate estimate.

Tech Notes for P0138 Pontiac

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 Pontiac Code

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

- 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) indicate in a Pontiac?

- This code indicates that the oxygen sensor in Bank 1 Sensor 2 is detecting a high voltage condition.

3. What are some possible causes of OBDII code P0138 in a Pontiac?

- Potential causes include a faulty oxygen sensor, wiring issues, exhaust leaks, engine misfires, or a malfunctioning catalytic converter.

4. How can I diagnose the OBDII code P0138 in my Pontiac?

- Diagnosing this code involves using an OBDII scanner to read the code, checking the oxygen sensor voltage levels, inspecting the wiring for damage, and testing the sensor's functionality.

5. Can I continue driving my Pontiac with the OBDII code P0138?

- It is not recommended to drive your vehicle with this code as it can lead to decreased fuel efficiency and potentially cause damage to the catalytic converter.

6. Is it safe to ignore the OBDII code P0138 in my Pontiac?

- Ignoring this code can lead to more serious issues over time, such as reduced engine performance and increased emissions. It is best to address the underlying problem promptly.

7. How can I repair the OBDII code P0138 in my Pontiac?

- Repairing this code typically involves replacing the Bank 1 Sensor 2 oxygen sensor, repairing any damaged wiring, and clearing the code from the vehicle's computer.

8. Can I replace the oxygen sensor myself to fix the OBDII code P0138 in my Pontiac?

- If you have the necessary tools and experience, you can replace the oxygen sensor yourself. However, if you are unsure, it is recommended to seek professional help for proper installation.

9. Will resetting the check engine light resolve the OBDII code P0138 in my Pontiac?

- Resetting the check engine light may temporarily turn it off, but it will not fix the underlying issue causing the code. It is important to diagnose and repair the problem to prevent it from reoccurring.

10. How much does it typically cost to repair the OBDII code P0138 in a Pontiac?

- The cost of repairing this code can vary depending on the cause of the issue, but it typically ranges from $100 to $300 for parts and labor.

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