AutoCodes – Hummer – P0172 Hummer

P0172 Hummer Code - Fuel Trim System Rich Bank 1

Quick Answer

The Engine Control Module (ECM) controls a Closed Loop air/fuel metering system to provide the best possible combination of drivability, fuel economy, and emission control. Common causes include Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air Leaks, Exhaust Gas Leaks. 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 Hummer indicates Fuel Trim System Rich Bank 1.
Common causes: Common causes include Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air Leaks, Exhaust Gas Leaks.
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.

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Code Popularity 9,805

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 29, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0172 Hummer Description

The Engine Control Module (ECM) controls a Closed Loop air/fuel metering system to provide the best possible combination of drivability, fuel economy, and emission control. The ECM monitors the Heated Oxygen Sensor (HO2S) signal voltage and adjusts the fuel delivery based on the signal voltage while in Closed Loop. A change made to the fuel delivery changes the long and short-term fuel trim values. The short-term fuel trim values change rapidly in response to the HO2S signal voltages. These changes fine-tune the engine fueling. The long-term fuel trim values change in response to trends in the short-term fuel trim. The long-term fuel trim makes coarse adjustments to fueling to re-center and restore control to short-term fuel trim. The ideal fuel trim values are around 0 %. A positive fuel trim value indicates that the ECM is adding fuel to compensate for a lean condition. A negative fuel trim value indicates that the ECM is reducing the amount of fuel to compensate for a rich condition. The Diagnostic Trouble Code (DTC) will be set when the average long-term fuel trim weighted average value is greater or less than a calibrated value.

OBDII Code P0172 Hummer - Fuel Trim System Rich Bank 1 - AutoCodes.com — P0172 Hummer Code - Fuel Trim System Rich Bank 1

What does this mean?

What are the Possible Causes of the DTC P0172 Hummer?

Dirty or Faulty Mass Air Flow (MAF) Sensor
Intake Air Leaks
Exhaust Gas Leaks
Fuel Contamination
Faulty or Leaking Fuel Injectors
Faulty Front Heated Oxygen Sensor
Ignition Misfiring
Incorrect Fuel Pressure
Positive Crankcase Ventilation (PCV) Hose Leaks

How to Fix the DTC P0172 Hummer?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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

There is a Factory Service Bulletin for the following HUMMER models:
2003-2008 HUMMER H2
2006-2008 HUMMER H3
2003-2008 HUMMER Factory Service Bulletin OBDII Code P0172

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0172 Hummer code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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Need more information on how to fix the P0172 Hummer code? Get Access to Factory Service Manuals

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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.

Frequently Asked Questions about P0172 Hummer Code

1. What does OBDII code P0172 for a Hummer indicate?

- The code P0172 on a Hummer signifies that the fuel trim system on Bank 1 is detecting a rich condition.

2. What are the common symptoms of an OBDII code P0172 on a Hummer?

- Common symptoms of P0172 in a Hummer may include decreased fuel efficiency, rough idling, and a noticeable decrease in engine performance.

3. What are some possible causes of the OBDII code P0172 on a Hummer?

- Some potential causes of code P0172 in a Hummer include a faulty oxygen sensor, a clogged fuel injector, a dirty air filter, or a vacuum leak.

4. How can I diagnose the issue related to OBDII code P0172 on my Hummer?

- To diagnose the problem, you can use an OBDII scanner to read the code, visually inspect the oxygen sensor and air filter, check for vacuum leaks, and test the fuel injectors.

5. Is it safe to continue driving my Hummer with an OBDII code P0172?

- It is not recommended to continue driving your Hummer with a P0172 code, as running too rich can lead to damage to the catalytic converter and other engine components.

6. How can I repair the issue causing the OBDII code P0172 on my Hummer?

- Repairing a P0172 code may involve replacing the oxygen sensor, cleaning or replacing the air filter, fixing any vacuum leaks, or servicing the fuel injectors.

7. Can a dirty MAF sensor trigger the OBDII code P0172 on a Hummer?

- Yes, a dirty or faulty MAF (Mass Air Flow) sensor can disrupt the air-to-fuel ratio, potentially leading to a rich condition and triggering the P0172 code.

8. Will a fuel system cleaning help resolve the OBDII code P0172 on my Hummer?

- Performing a fuel system cleaning may help address a P0172 code if the issue is related to clogged fuel injectors or a dirty fuel system.

9. How long does it typically take to repair the issue causing the OBDII code P0172 on a Hummer?

- The repair time for a P0172 code on a Hummer can vary depending on the exact cause, but it may take anywhere from a few hours to a full day to diagnose and fix the problem.

10. Should I reset the OBDII code P0172 after making repairs on my Hummer?

- Yes, it is recommended to reset the code after making the necessary repairs to see if the issue has been resolved.