Engine-CodesGMC – P1133 2018 GMC Sierra

P1133 2018 GMC Sierra Code - HO2S Insufficient Switching Bank 1 Sensor 1

Quick Answer

The P1133 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates an issue with the HO2S (Heated Oxygen Sensor) insufficient switching on Bank 1 Sensor 1. Common causes include Faulty HO2S, Wiring issues or corrosion, Exhaust leaks near 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
P1133 2018 GMC Sierra indicates HO2S Insufficient Switching Bank 1 Sensor 1.
Common causes
Common causes include Faulty HO2S, Wiring issues or corrosion, Exhaust leaks near 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 14, 2024
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Code P1133 2018 GMC Sierra Description

The P1133 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates an issue with the HO2S (Heated Oxygen Sensor) insufficient switching on Bank 1 Sensor 1. This sensor 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. When the sensor fails to switch between rich and lean air-fuel ratios quickly enough, it can lead to performance issues and increased emissions.

OBDII Code P1133 2018 GMC Sierra - HO2S Insufficient Switching Bank 1 Sensor 1
P1133 2018 GMC Sierra Code - HO2S Insufficient Switching Bank 1 Sensor 1

Common Causes of P1133 2018 GMC Sierra

  1. Faulty HO2S
  2. Wiring issues or corrosion
  3. Exhaust leaks near the sensor
  4. Malfunctioning ECM
  5. Contaminated sensor due to oil or coolant leaks

Symptoms of P1133 2018 GMC Sierra

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

How to Fix P1133 2018 GMC Sierra

  1. Begin by diagnosing the specific cause of the insufficient switching, such as testing the HO2S with a multimeter or scan tool.
  2. Inspect the wiring harness for any damage or corrosion, repairing or replacing as needed.
  3. Check for exhaust leaks near the sensor and repair them to prevent false readings.
  4. Replace the Bank 1 Sensor 1 HO2S if it is determined to be faulty.
  5. Clear the DTC and perform a test drive to ensure the issue has been resolved.

Cost to Fix P1133 2018 GMC Sierra

The typical repair costs for addressing a P1133 code on a 2018 GMC Sierra can range from $150 to $400, including parts and labor. However, it is essential to note that specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. Most auto repair shops charge between $80 and $150 per hour for labor, but rates may be higher in metropolitan areas or at dealerships, while independent shops may offer lower rates. It is advisable to inquire about local rates for a more accurate estimate.

Tech Notes for P1133 2018 GMC Sierra

Replacing the Front Heated Oxygen Sensors (HO2S) 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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