Engine-CodesGMC – P0138 2017 GMC Sierra

P0138 2017 GMC Sierra Code - HO2S Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The P0138 diagnostic trouble code (DTC) for a 2017 GMC Sierra refers to a problem with the HO2S (Heated Oxygen Sensor) Circuit High Voltage for Bank 1 Sensor 2. Common causes include Faulty oxygen sensor, Damaged wiring or connectors in the sensor circuit, Vacuum leaks. 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 2017 GMC Sierra indicates HO2S Circuit High Voltage Bank 1 Sensor 2.
Common causes
Common causes include Faulty oxygen sensor, Damaged wiring or connectors in the sensor circuit, Vacuum leaks.
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 16, 2024
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Code P0138 2017 GMC Sierra Description

The P0138 diagnostic trouble code (DTC) for a 2017 GMC Sierra refers to a problem with the HO2S (Heated Oxygen Sensor) Circuit High Voltage 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 high voltage indicated in the code suggests that the sensor is detecting a higher than normal voltage level, which can lead to incorrect fuel mixture readings and affect the vehicle's performance.

OBDII Code P0138 2017 GMC Sierra - HO2S Circuit High Voltage Bank 1 Sensor 2
P0138 2017 GMC Sierra Code - HO2S Circuit High Voltage Bank 1 Sensor 2

Common Causes of P0138 2017 GMC Sierra

  1. Faulty oxygen sensor
  2. Damaged wiring or connectors in the sensor circuit
  3. Vacuum leaks
  4. Exhaust leaks
  5. Issues with the engine control module (ECM)

Symptoms of P0138 2017 GMC Sierra

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Hesitation or lack of power during acceleration
  4. Check Engine Light illuminated on the dashboard

How to Fix P0138 2017 GMC Sierra

  1. Begin by conducting a visual inspection of the oxygen sensor and its wiring to check for any visible damage or corrosion.
  2. Use a multimeter to test the voltage output of the sensor and compare it to the manufacturer's specifications.
  3. If the sensor is faulty, replace it with a new, OEM-quality sensor.
  4. Check and repair any damaged wiring or connectors in the sensor circuit.
  5. Clear the DTC with a scan tool and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0138 2017 GMC Sierra

The typical repair costs for addressing a P0138 code on a 2017 GMC Sierra can range from $150 to $400, depending on the specific cause of the issue and the cost of parts and labor in your area. It's important to note that diagnosis time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate. Keep in mind that rates may be higher at dealerships or in metropolitan areas, while independent shops may offer more competitive pricing.

Tech Notes for P0138 2017 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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