Engine-CodesGMC – P0138 2014 GMC Sierra

P0138 2014 GMC Sierra Code - HO2S Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The P0138 diagnostic trouble code (DTC) for a 2014 GMC Sierra indicates an issue with the HO2S (Heated Oxygen Sensor) Circuit High Voltage for Bank 1 Sensor 2. Common causes include Faulty HO2S sensor, Damaged wiring or 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 2014 GMC Sierra indicates HO2S Circuit High Voltage Bank 1 Sensor 2.
Common causes
Common causes include Faulty HO2S sensor, Damaged wiring or 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.
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P0138 2014 GMC Sierra Description

The P0138 diagnostic trouble code (DTC) for a 2014 GMC Sierra indicates an issue with the HO2S (Heated Oxygen Sensor) Circuit High Voltage for Bank 1 Sensor 2. This sensor is responsible for measuring the oxygen content in the exhaust gases and sending this information to the engine control module (ECM) for optimal fuel delivery. When the sensor detects a high voltage signal, it means that the oxygen content in the exhaust is too low, which can lead to a rich air-fuel mixture.

OBDII Code P0138 2014 GMC Sierra - HO2S Circuit High Voltage Bank 1 Sensor 2
P0138 2014 GMC Sierra Code - HO2S Circuit High Voltage Bank 1 Sensor 2

Common Causes of P0138 2014 GMC Sierra

  1. Faulty HO2S sensor
  2. Damaged wiring or connectors
  3. Exhaust leaks near the sensor
  4. Malfunctioning ECM
  5. Contaminated exhaust gases affecting sensor readings

Symptoms of P0138 2014 GMC Sierra

  1. Decreased fuel efficiency
  2. Rough idling
  3. Hesitation during acceleration
  4. Engine misfires
  5. Check Engine Light illuminated on the dashboard

How to Fix P0138 2014 GMC Sierra

  1. Diagnose the issue by using a scan tool to read the code and determine the specific cause.
  2. Inspect the wiring and connectors for any damage or corrosion and repair as necessary.
  3. Test the HO2S sensor using a multimeter to check for proper voltage readings.
  4. Replace the HO2S sensor if it is faulty or contaminated.
  5. Clear the code with a scan tool and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0138 2014 GMC Sierra

The cost of repairing a P0138 code on a 2014 GMC Sierra can vary depending on the specific cause of the issue. Generally, replacing a faulty HO2S sensor can range from $100 to $200, including parts and labor. However, if additional wiring repairs or an ECM replacement are needed, the cost can increase significantly. It is advisable to consult with a professional mechanic or auto repair shop for an accurate estimate based on the specific diagnosis and parts needed for the repair. Labor rates at auto repair shops typically range from $80 to $150 per hour, so the total cost can vary based on location and the shop's rates.

Tech Notes for P0138 2014 GMC Sierra

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.

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