How to Troubleshoot P0174 Code on GMC Acadia

AvatarByCarl Frisch

P0174 is a diagnostic trouble code (DTC) for the GMC Acadia. This code indicates that the engine control module (ECM) has detected an imbalance in the air-fuel mixture. The ECM adjusts the air-fuel mixture by using sensors located before and after the catalytic converter to detect oxygen levels in the exhaust system. If the oxygen levels on one side of the catalytic converter are too high, it could indicate a lean air-fuel mixture, which can result in poor fuel economy, hesitation during acceleration, and rough idling. Common causes of this code include an air intake leak, a vacuum leak, an incorrect fuel pressure regulator, or a faulty mass airflow sensor.

What is the P0174 Code?

The P0174 code is a generic trouble code for a problem with the air/fuel mixture in the GMC Acadia’s engine. This code is typically caused by an issue with the air intake system, fuel injection system, mass airflow sensor (MAF), intake manifold tuning valve (IMTV), or oxygen sensor (O2). The P0174 code is triggered when the Engine Control Unit (ECU) detects an imbalance between the actual air/fuel ratio and the ideal air/fuel ratio.

Common Issues with the GMC Acadia that can Cause the P0174 Code

There are several common issues with the GMC Acadia that can cause a P0174 code. These include a faulty mass airflow sensor, clogged fuel injectors, vacuum leaks, and an incorrect IMTV setting. Other issues that can cause this code to be triggered include a faulty oxygen sensor or an inadequate fuel pressure regulator.

Symptoms of a P0174 Code

When a P0174 code is present in the GMC Acadia, there are usually several symptoms present as well. Common symptoms of this code include reduced engine power, poor fuel economy, rough idle, stalling, and misfires. In some cases, there may also be a Check Engine Light illuminated on the dashboard.

Tools Needed to Diagnose a P0174 Code

In order to properly diagnose and repair a P0174 code in a GMC Acadia, there are several tools that will be needed. These tools include an OBD-II scanner, multimeter or scan tool tester to test components such as sensors and relays. In addition to these tools, you may also need specialized equipment such as smoke testers and vacuum pumps for testing vacuum leaks in your vehicle’s intake system.

Diagnostic Steps for Troubleshooting a P0174 Code

When diagnosing and troubleshooting a P0174 code in your GMC Acadia it is important to follow specific steps in order to properly identify and repair any issues present. The first step should always be to use an OBD-II scanner to read any codes stored in your vehicle’s ECU memory. From here you should then inspect all of your vehicle’s air intake components such as filters and hoses for any signs of wear or damage that could be causing an imbalance in your air/fuel mixture. Once these components have been inspected you should then move on to testing all of your sensors including MAFs, IMTVs and oxygen sensors using either multimeters or scan tool testers if necessary. After checking all of these components if no issues are found then you should check for any vacuum leaks using specialized smoke testing equipment or vacuum pumps if necessary which can be found at most auto parts stores. Once all possible causes have been checked it is important that you reset your ECU memory before road testing your vehicle again in order to ensure that all of the codes have been cleared from memory before further diagnosis can begin again if necessary.

Parts Needed to Replace for Repairing a P0174 Code

When troubleshooting the GMC Acadia’s P0174 code, there are a few parts that may need to be replaced. These parts include items from the air intake system, fuel injection system, mass airflow sensor (MAF), intake manifold tuning valve (IMTV), oxygen sensor (O2), and vacuum leak components. The cost of these parts will depend on the make and model of the car as well as the local market prices.

Air Intake System Parts

The air intake system is responsible for bringing in outside air into the engine. This air is then mixed with fuel and burned in order to create power. If there is a problem with this system, it can cause an incorrect fuel/air mixture which can lead to a P0174 code being triggered. Parts that may need to be replaced include the air filter, throttle body, intake manifold gasket, and vacuum hoses.

Fuel Injection System Parts

The fuel injection system is responsible for delivering fuel into the engine at precise times in order to create an optimal combustion process. If this system is not functioning properly it can cause an incorrect fuel/air mixture which can lead to a P0174 code being triggered. Parts that may need to be replaced include fuel injectors, fuel pressure regulator, and spark plugs.

Mass Airflow Sensor (MAF)

The mass airflow sensor measures how much air is entering the engine at any given time so that it can adjust the amount of fuel being injected accordingly. If this sensor malfunctions due to age or debris build-up it can cause an incorrect fuel/air mixture which can lead to a P0174 code being triggered. The MAF needs to be cleaned or replaced if it is malfunctioning in order for the engine to run correctly again.

Intake Manifold Tuning Valve (IMTV)

The intake manifold tuning valve helps regulate the amount of air entering the engine by controlling how much vacuum is created within the intake manifold when certain conditions are met. If this valve fails due to age or debris build-up it can cause an incorrect fuel/air mixture which can lead to a P0174 code being triggered. The IMTV needs to be cleaned or replaced if it is malfunctioning in order for the engine to run correctly again.

Oxygen Sensor (O2)

The oxygen sensor measures how much oxygen is present in the exhaust gases coming out of the engine so that adjustments can be made in order for optimal combustion efficiency. If this sensor fails due to age or debris build-up it can cause an incorrect fuel/air mixture which can lead to a P0174 code being triggered . The O2 needs to be cleaned or replaced if it is malfunctioning in order for the engine to run correctly again .

Vacuum Leak Parts

Vacuum leaks occur when there are cracks or holes present in any of the vacuum hoses or components connected with them . This causes outside air from entering into certain parts of the engine where it should not and therefore causing an incorrect fuel/air mixture . This type of issue will usually set off a P0174 code . In order fix this type of problem , all vacuum hoses and components must be inspected and any faulty pieces must be replaced .

FAQ & Answers

Q: What is the P0174 Code?
A: The P0174 code is a diagnostic trouble code (DTC) for a system too lean (Bank 2). This code indicates that the air/fuel mixture in the engine is too low on fuel and too high on air.

Q: What are Common Issues with the GMC Acadia that can Cause the P0174 Code?
A: Common issues with the GMC Acadia that can cause the P0174 code include an incorrect fuel/air mixture, vacuum leaks, and a bad mass airflow sensor.

Q: What are Symptoms of a P0174 Code?
A: Symptoms of a P0174 code can include reduced fuel efficiency, stalling, and misfires. Additionally, you may also experience decreased power when accelerating.

Q: What Tools are Needed to Diagnose a P0174 Code?
A: To diagnose a P0174 code, you will need an OBD-II scanner and other diagnostic tools such as an oscilloscope or multimeter. Additionally, it is helpful to have access to OEM repair information for your vehicle.

Q: What are Diagnostic Steps for Troubleshooting a P0174 code?
A: Diagnostic steps for troubleshooting a P0174 code include checking for air intake system issues, fuel injection system issues, mass airflow sensor (MAF) issues, intake manifold tuning valve (IMTV) issues, oxygen sensor (O2) issues, and vacuum leaks. It is important to follow each step in order to accurately diagnose and repair the issue.

In conclusion, the P0174 code GMC Acadia is a fairly common engine fault code that can affect the overall performance and efficiency of the vehicle. While this code can be caused by a variety of issues, it is important to diagnose and repair the problem as soon as possible in order to maintain the reliability and performance of your vehicle. With proper care and maintenance, you can ensure that your GMC Acadia will continue to provide you with reliable transportation for years to come.

Author Profile

Carl Frisch
Carl Frisch
With more than 30 years in the bicycle industry, I have a strong background in bicycle retailing, sales, marketing and customer service. I have a passion for cycling and a dedication to excellence. As a manager, I worked diligently to increase my capabilities and responsibilities, managing up to eleven mechanics (at Palo Alto Bicycles) and later as a working partner in my own store.

As the shop owner of Spoke n’ Word Cycles in Socorro, NM, the success of the mission was my responsibility, which I pursued passionately since we opened in 2003 through the spring of 2011. I am adept at managing owned and loan inventory, preparing weekly & annual inventory statements, and managing staff. The role as managing partner also allowed me tremendous freedom. I used this personal freedom to become more deeply involved in my own advancement as a mechanic, to spearhead local trail building, and advocating for cycling both locally and regionally.

As a mechanic, I have several years doing neutral support, experience as a team mechanic, and experience supporting local rides, races, club events. I consistently strive to ensure that bicycles function flawlessly by foreseeing issues and working with the riders, soigners, coaches and other mechanics. Even with decades of experience as a shop mechanic and team mechanic, and continue to pursue greater involvement in this sport as a US Pro Mechanic, and UCI Pro Mechanic.

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