AutoCodes – Nissan – P0171 2004 Nissan Altima_sedan

P0171 2004 Nissan Altima_sedan Code - Fuel Injection System Too Lean Bank 1

Quick Answer

With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. 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 2004 Nissan Altima_sedan indicates Fuel Injection System Too 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 7,448

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 Jul 20, 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 2004 Nissan Altima_sedan Description

With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).

OBDII Code P0171 2004 Nissan Altima_sedan - Fuel Injection System Too Lean Bank 1 - AutoCodes.com — P0171 2004 Nissan Altima_sedan Code - Fuel Injection System Too Lean Bank 1

What does this mean?

What are the Possible Causes of the DTC P0171 2004 Nissan Altima_sedan?

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 2004 Nissan Altima_sedan?

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0171 2004 Nissan Altima_sedan 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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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 2004 Nissan Altima_sedan Code

1. What does the OBDII code P0171 mean for a 2004 Nissan Altima sedan?

The code P0171 indicates that the fuel injection system on bank 1 of the engine is running too lean.

2. What are the common symptoms of OBDII code P0171 on a 2004 Nissan Altima sedan?

Common symptoms include rough idling, poor acceleration, decreased fuel efficiency, and the illumination of the check engine light.

3. What are the possible causes of code P0171 on a 2004 Nissan Altima sedan?

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

4. How can I diagnose the cause of OBDII code P0171 on my 2004 Nissan Altima sedan?

Diagnosing the issue may involve checking for vacuum leaks, inspecting the oxygen sensor, testing the fuel pressure, examining the mass airflow sensor, and ensuring proper fuel injector function.

5. Can a dirty air filter trigger code P0171 on a 2004 Nissan Altima sedan?

Yes, a dirty air filter can disrupt the air-to-fuel ratio, leading to a lean condition and potentially triggering the P0171 trouble code.

6. How can I repair OBDII code P0171 on my 2004 Nissan Altima sedan?

Repair options may involve fixing any vacuum leaks, replacing the oxygen sensor, cleaning or replacing the mass airflow sensor, ensuring proper fuel pressure, and addressing any fuel injector issues.

7. Is it safe to continue driving with OBDII code P0171 on a 2004 Nissan Altima sedan?

It is not recommended to continue driving with code P0171 as it can lead to engine damage over time. It's important to address the underlying issue promptly.

8. Will resetting the check engine light make OBDII code P0171 disappear on a 2004 Nissan Altima sedan?

Resetting the check engine light may temporarily clear the code, but if the underlying issue causing P0171 is not fixed, the code is likely to reappear after driving for some time.

9. Can a bad fuel pump cause OBDII code P0171 on a 2004 Nissan Altima sedan?

A failing fuel pump can indeed contribute to a lean fuel mixture, potentially triggering code P0171. It's advisable to check the fuel pump's functionality during diagnosis.

10. How often should I check for OBDII code P0171 on my 2004 Nissan Altima sedan?

Regularly monitoring your vehicle for symptoms of a lean condition and promptly addressing any issues can help prevent the recurrence of code P0171 on your 2004 Nissan Altima sedan.