AutoCodes – Pontiac – P0174 Pontiac

P0174 Pontiac Code - Fuel Trim System Lean Bank 2

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 Restricted Air Filter, Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air 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: P0174 Pontiac indicates Fuel Trim System Lean Bank 2.
Common causes: Common causes include Dirty or Restricted Air Filter, Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air 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 19,303

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 Aug 21, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0174 Pontiac 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 P0174 Pontiac - Fuel Trim System Lean Bank 2 - AutoCodes.com — P0174 Pontiac Code - Fuel Trim System Lean Bank 2

What does this mean?

What are the Possible Causes of the DTC P0174 Pontiac?

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

How to Fix the DTC P0174 Pontiac?

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 P0174 code means that more air than gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0174 is set in along with the P0171 code, it is highly likely that the problem is caused by an intake leak. If there are no intake leaks, 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 are Factory Service Bulletin for the following Pontiac models:

2000-2001 Pontiac Transport
2000-2002 Pontiac Firebird
2000-2008 Pontiac Bonneville
2000-2008 Pontiac Grand Am
2000-2008 Pontiac Grand Prix
2000-2008 Pontiac Sunfire
2001-2008 Pontiac Aztek
2002-2008 Pontiac Montana
2000-2008 Pontiac Factory Service Bulletin OBDII Code P0174

2005-2006 Pontiac Grand Prix
2005-2006 Pontiac Grand Prix Service Bulletin OBDII Code P0174

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0174 Pontiac 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.

Need more information about the P0174 Pontiac code?

Need more information on how to fix the P0174 Pontiac code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0174 Pontiac code diagnosed by a professional: Find a repair shop in your area

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 P0174 Pontiac Code

1. What are the common symptoms of OBDII code P0174 on a Pontiac indicating a Fuel Trim System Lean Bank 2 issue?

- Common symptoms include rough idling, loss of power, engine stalling, poor fuel economy, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P0174 on a Pontiac?

- Potential causes may include a vacuum leak, faulty oxygen sensors, a clogged fuel filter, a malfunctioning mass airflow sensor, or issues with the fuel injectors.

3. How can I diagnose the OBDII code P0174 on my Pontiac?

- Diagnosis involves using an OBDII scanner to retrieve the code, checking for any other related codes, inspecting the vacuum lines, testing the oxygen sensors, examining the air intake system, and looking for any signs of fuel leaks.

4. Can a dirty or clogged air filter trigger the OBDII code P0174 on a Pontiac?

- Yes, a dirty or clogged air filter can disrupt the air-fuel mixture ratio, potentially leading to a lean condition and triggering the P0174 code.

5. Is it safe to continue driving my Pontiac with the OBDII code P0174 present?

- It is not recommended to drive the vehicle with the P0174 code as it can cause further damage to the engine and negatively impact its performance.

6. How can I repair the OBDII code P0174 on my Pontiac?

- Repairs may involve replacing the oxygen sensors, cleaning or replacing the mass airflow sensor, fixing any vacuum leaks, checking the fuel pressure, and ensuring proper operation of the fuel injectors.

7. Can a faulty catalytic converter be a cause of the OBDII code P0174 on a Pontiac?

- Yes, a faulty catalytic converter can cause an imbalance in the air-fuel mixture, leading to a lean condition and triggering the P0174 code.

8. Are there any DIY fixes for the OBDII code P0174 on a Pontiac?

- DIY fixes may include checking and tightening the gas cap, inspecting and cleaning the air filter, and visually inspecting the vacuum lines for any visible damage.

9. How long does it typically take to repair the OBDII code P0174 issue on a Pontiac?

- The repair time can vary depending on the exact cause of the problem, but it may take a few hours to a full day to diagnose and fix the issue properly.

10. What is the importance of addressing the OBDII code P0174 promptly on a Pontiac?

- It is crucial to address the P0174 code promptly to prevent further damage to the engine, ensure optimal fuel efficiency, and maintain the overall performance and reliability of the vehicle.