Engine-CodesChevrolet – P1139 Chevrolet

P1139 Chevrolet Code - HO2S Insufficient Switching Bank 1 Sensor 2

Quick Answer

The P1139 Chevrolet code indicates that there is an issue with the HO2S (Heated Oxygen Sensor) insufficient switching on Bank 1 Sensor 2. Common causes include Faulty oxygen sensor, Wiring issues (shorts, opens, or poor connections), Exhaust leaks before the sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1139 Chevrolet indicates HO2S Insufficient Switching Bank 1 Sensor 2.
Common causes
Common causes include Faulty oxygen sensor, Wiring issues (shorts, opens, or poor connections), Exhaust leaks before the sensor.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code P1139 Chevrolet Description

The P1139 Chevrolet code indicates that there is an issue with the HO2S (Heated Oxygen Sensor) insufficient switching on Bank 1 Sensor 2. The HO2S is responsible for 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. Bank 1 refers to the side of the engine where cylinder 1 is located, and Sensor 2 indicates that it is the downstream sensor located after the catalytic converter.

OBDII Code P1139 Chevrolet - HO2S Insufficient Switching Bank 1 Sensor 2
P1139 Chevrolet Code - HO2S Insufficient Switching Bank 1 Sensor 2

Common Causes of P1139 Chevrolet

  1. Faulty oxygen sensor
  2. Wiring issues (shorts, opens, or poor connections)
  3. Exhaust leaks before the sensor
  4. Vacuum leaks affecting sensor readings
  5. Internal engine problems affecting air-fuel mixture

Symptoms of P1139 Chevrolet

  1. Decreased fuel efficiency
  2. Rough idle or stalling
  3. Engine hesitation during acceleration
  4. Increased emissions output
  5. Check Engine Light illuminated

How to Fix P1139 Chevrolet

  1. Diagnose the issue using a scan tool to retrieve the specific trouble code and sensor data.
  2. Inspect the oxygen sensor and wiring for any visible damage or corrosion.
  3. Test the sensor's response using a multimeter or oscilloscope to verify proper switching.
  4. Replace the oxygen sensor if it is faulty or not switching correctly.
  5. Clear the trouble code and perform a test drive to ensure the issue has been resolved.

Cost to Fix P1139 Chevrolet

The typical repair costs for addressing a P1139 Chevrolet code can range from $150 to $400, including the cost of the oxygen sensor and labor. Keep in mind that prices may vary depending on the specific vehicle make and model, location, and the shop's labor rates. It is recommended to consult with a trusted mechanic or repair shop for a more accurate estimate based on your individual circumstances.

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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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