AutoCodes – Oldsmobile – P0174 Oldsmobile

P0174 Oldsmobile 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 Oldsmobile 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 8,916

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 Oldsmobile 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 Oldsmobile - Fuel Trim System Lean Bank 2 - AutoCodes.com — P0174 Oldsmobile Code - Fuel Trim System Lean Bank 2

What does this mean?

What are the Possible Causes of the DTC P0174 Oldsmobile?

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 Oldsmobile?

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 is a Factory Service Bulletin for the following Oldsmobile models:
2000-2004 Oldsmobile Alero
2000-2005 Oldsmobile Silhouette
2002-2004 Oldsmobile Bravada
2000-2004 Oldsmobile Factory Service Bulletin OBDII Code P0174

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0174 Oldsmobile 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 Oldsmobile code?

Need more information on how to fix the P0174 Oldsmobile 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 P0174 Oldsmobile Code

1. What are the common symptoms of OBDII code P0174 in an Oldsmobile related to the Fuel Trim System Lean Bank 2?

- Common symptoms include rough idling, poor acceleration, decreased fuel efficiency, and potential misfires.

2. What are the possible causes of OBDII code P0174 in an Oldsmobile indicating a lean condition in Bank 2?

- Causes may include a vacuum leak, faulty oxygen sensor, clogged fuel filter, malfunctioning mass airflow sensor, or a problem with the fuel injectors.

3. How can I diagnose the issue causing OBDII code P0174 in my Oldsmobile?

- Diagnose the problem by performing a visual inspection for leaks, checking the oxygen sensor readings, testing the fuel pressure, and inspecting the air intake system components.

4. Can a dirty or failing mass airflow sensor trigger OBDII code P0174 in an Oldsmobile?

- Yes, a dirty or failing mass airflow sensor can disrupt the air-to-fuel ratio, leading to a lean condition in Bank 2 and triggering the P0174 code.

5. Is it safe to continue driving my Oldsmobile with OBDII code P0174 indicating a lean condition in Bank 2?

- It is not recommended to drive the vehicle for an extended period with this issue, as it can lead to engine damage and further complications if left unresolved.

6. How can I repair OBDII code P0174 in my Oldsmobile Fuel Trim System Lean Bank 2?

- Repair options include fixing any vacuum leaks, replacing the oxygen sensor, cleaning or replacing the mass airflow sensor, checking and replacing the fuel filter, and ensuring proper fuel injector function.

7. Can a clogged fuel filter cause OBDII code P0174 in an Oldsmobile?

- Yes, a clogged fuel filter can restrict fuel flow and disrupt the air-to-fuel ratio, resulting in a lean condition in Bank 2 and triggering the P0174 code.

8. Will resetting the OBDII system clear the P0174 code in my Oldsmobile?

- Resetting the system may temporarily clear the code, but if the underlying issue causing the lean condition in Bank 2 is not addressed, the code is likely to reappear.

9. How do I prevent OBDII code P0174 from coming back in my Oldsmobile after repair?

- Regular maintenance, such as replacing the fuel filter, cleaning sensors, and fixing leaks promptly, can help prevent the recurrence of the P0174 code.

10. Can a faulty oxygen sensor cause OBDII code P0174 in an Oldsmobile?

- Yes, a faulty oxygen sensor can provide inaccurate readings to the engine control module, leading to a lean condition in Bank 2 and triggering the P0174 code.