Engine-CodesGMC – P0172 2018 GMC Sierra

P0172 2018 GMC Sierra Code - Fuel Trim System Rich Bank 1

Quick Answer

The P0172 code for a 2018 GMC Sierra indicates that the fuel trim system on bank 1 is running rich. Common causes include Faulty fuel injectors, Clogged fuel filter, Malfunctioning mass airflow 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
P0172 2018 GMC Sierra indicates Fuel Trim System Rich Bank 1.
Common causes
Common causes include Faulty fuel injectors, Clogged fuel filter, Malfunctioning mass airflow 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 17, 2024
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Code P0172 2018 GMC Sierra Description

The P0172 code for a 2018 GMC Sierra indicates that the fuel trim system on bank 1 is running rich. This means that there is too much fuel being injected into the engine compared to the amount of air present. The fuel trim system is responsible for adjusting the air-fuel mixture to ensure optimal combustion and engine performance. When the system is running rich, it can lead to decreased fuel efficiency, increased emissions, and potential damage to the engine over time.

OBDII Code P0172 2018 GMC Sierra - Fuel Trim System Rich Bank 1
P0172 2018 GMC Sierra Code - Fuel Trim System Rich Bank 1

Common Causes of P0172 2018 GMC Sierra

  1. Faulty fuel injectors
  2. Clogged fuel filter
  3. Malfunctioning mass airflow sensor
  4. Leaking fuel pressure regulator
  5. Defective oxygen sensor on bank 1

Symptoms of P0172 2018 GMC Sierra

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Strong fuel odor from the exhaust
  4. Loss of engine power
  5. Black smoke coming from the exhaust

How to Fix P0172 2018 GMC Sierra

  1. Diagnose the issue using a scan tool to confirm the P0172 code and identify the specific component causing the rich condition.
  2. Inspect the fuel injectors, fuel filter, mass airflow sensor, and oxygen sensor on bank 1 for any signs of damage or malfunction.
  3. Clean or replace the faulty component, such as cleaning the fuel injectors or replacing a defective oxygen sensor.
  4. Reset the ECM to clear the code and monitor the air-fuel ratio to ensure it is within the correct range.
  5. Test drive the vehicle to verify that the issue has been resolved and the Check Engine Light does not reappear.

Cost to Fix P0172 2018 GMC Sierra

The cost of repairing a P0172 code on a 2018 GMC Sierra can vary depending on the specific cause of the rich condition. On average, the repair costs for this issue can range from $200 to $600, including parts and labor. However, it's important to note that the actual cost may be higher or lower based on the location, dealership rates, and the extent of the repairs needed. It's recommended to consult with a qualified mechanic or auto repair shop to get an accurate estimate for your specific vehicle.

Tech Notes for P0172 2018 GMC Sierra

The P0172 code means that more gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0172 is set in along with the P0175 code, it is highly likely that the problem is caused by leaking fuel injectors. If there are no leaking fuel injectors, the next step is to replace the air filter and clean the Mass Air Flow (MAF) Sensor. If the problem persists the MAF or Front Heated Oxygen (O2) Sensor will need to be replaced.



Click Here to Learn What is Bank 1 and Bank 2

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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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