AutoCodes – Oldsmobile – P0171 Oldsmobile

P0171 Oldsmobile Code - Fuel Trim System Lean Bank 1

Quick Answer

The Engine Control Module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Common causes include Intake air leaks, Faulty front heated oxygen sensor, Ignition misfiring. 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: P0171 Oldsmobile indicates Fuel Trim System Lean Bank 1.
Common causes: Common causes include Intake air leaks, Faulty front heated oxygen sensor, Ignition misfiring.
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 37,357

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 P0171 Oldsmobile Description

The Engine Control Module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the ECM adds HO2S inputs to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicates a rich condition, the FT values will be below 0 percent. The short term FT values change rapidly in response to the HO2S voltage signals. The long term FT makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

OBDII Code P0171 Oldsmobile - Fuel Trim System Lean Bank 1 - AutoCodes.com — P0171 Oldsmobile Code - Fuel Trim System Lean Bank 1

What does this mean?

What are the Possible Causes of the DTC P0171 Oldsmobile?

Intake air leaks
Faulty front heated oxygen sensor
Ignition misfiring
Faulty fuel injectors
Exhaust gas leaks
Incorrect fuel pressure
Lack of fuel
Faulty Mass Air Flow (MAF) sensor
Incorrect Positive Crankcase Ventilation (PCV) hose connection

How to Fix the DTC P0171 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

If the P0171 is combined with the P0174 code, it's very 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 air flow meter. If the problem persists the front oxygen (O2) sensor may need to be replaced.
The P0171 code could also be caused may be caused by one or more of the following: debris on the MAF sensor causing an incorrect reading, improper oil level, low or high fuel pressure, or Engine Control Temperature (ECT) Sensor reading inaccurate.

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 P0171

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0171 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 P0171 Oldsmobile code?

Need more information on how to fix the P0171 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 P0171 Oldsmobile Code

1. What are the common symptoms of OBDII code P0171 on an Oldsmobile?

- The common symptoms of code P0171 include rough idling, reduced fuel efficiency, lack of power, and the check engine light illuminating.

2. What are the potential causes of the Fuel Trim System Lean Bank 1 code on an Oldsmobile?

- Potential causes of code P0171 on an Oldsmobile include a vacuum leak, faulty Mass Air Flow (MAF) sensor, fuel system issues, or a malfunctioning oxygen sensor.

3. How can I diagnose the cause of OBDII code P0171 on my Oldsmobile?

- You can diagnose the cause of code P0171 by checking for vacuum leaks, inspecting the MAF sensor, testing the oxygen sensor, and analyzing fuel pressure and injector performance.

4. Is it safe to continue driving my Oldsmobile with code P0171 present?

- It is generally not recommended to continue driving your Oldsmobile with code P0171 present, as it can lead to more serious issues and potential damage to the engine over time.

5. How can I repair OBDII code P0171 on my Oldsmobile?

- To repair code P0171 on your Oldsmobile, you may need to fix any vacuum leaks, replace a faulty MAF sensor, address fuel system issues, or replace a malfunctioning oxygen sensor.

6. Can a dirty air filter cause OBDII code P0171 on an Oldsmobile?

- Yes, a dirty air filter can contribute to code P0171 by affecting the air-fuel mixture, leading to a lean condition in the fuel trim system.

7. Will resetting the OBDII code P0171 on my Oldsmobile make it go away permanently?

- Simply resetting the code may temporarily clear the check engine light, but if the underlying issue causing P0171 is not addressed, the code is likely to reappear.

8. How can I prevent OBDII code P0171 from returning on my Oldsmobile?

- To prevent code P0171 from reoccurring, perform regular maintenance, address any potential causes promptly, and ensure the air intake system is clean and free of leaks.

9. Can a clogged fuel filter trigger OBDII code P0171 on an Oldsmobile?

- Yes, a clogged fuel filter can restrict fuel flow, leading to a lean condition in the fuel trim system and potentially triggering code P0171.

10. Is it necessary to visit a mechanic to fix OBDII code P0171 on my Oldsmobile?

- While some simple causes of code P0171 can be addressed by DIY enthusiasts, it is recommended to consult a mechanic for proper diagnosis and repair to ensure the issue is resolved effectively.