OBD code P0171 indicates that the air-to-fuel ratio in the engine’s Bank 1 is too lean, meaning there is too much air and not enough fuel. This can be caused by a variety of issues including a vacuum leak, faulty oxygen sensor, or a clogged fuel injector.
1. What are the possible symptoms ?
1. Rough idling
2. Hesitation or stumbling during acceleration
3. Misfiring
4. Decreased fuel efficiency
5. Check Engine Light illuminated
2. What are the most probable causes ?
1. Vacuum leaks
2. Faulty oxygen sensor
3. Dirty or clogged fuel injectors
4. Low fuel pressure
5. Exhaust leaks
6. Mass air flow sensor malfunction
7. Restricted air intake system
8. Faulty PCV system
3. Is it safe to drive with this fault not fixed?
It is not recommended to drive the vehicle with the OBD fault code P0171-System Too Lean –Bank 1 as it can lead to potential engine damage.
4. What is the severity level of this fault code ?
The OBD code P0171 indicates that the engine is running too lean, which can be a serious issue if left unchecked. It is a fairly common fault that can occur due to various reasons such as vacuum leaks, faulty oxygen sensors, or a clogged fuel filter.
5. How much will cost to repair this fault ?
The cost to repair the OBD fault code P0171 can vary depending on the specific issue causing the lean condition, but it may range from $100 to $500 for parts and labor. Common repairs include replacing a faulty oxygen sensor, repairing vacuum leaks, or cleaning the mass airflow sensor.
6. Troubleshooting – List of most reported fixes :
1. Check for vacuum leaks in the air intake system and repair any leaks found.
2. Clean or replace the mass airflow sensor to ensure accurate air flow measurements.
3. Inspect and clean the fuel injectors to improve fuel delivery and combustion efficiency.
7. What are the most affected components by this fault code ?
1. Mass Airflow Sensor (MAF)
2. Exhaust System
3. Oxygen Sensor
4. Fuel System (Injectors, Pressure Regulator)
5. Vacuum Leaks
8. Several risks you may face if this issue is not fixed :
1. Reduced fuel efficiency.
2. Potential damage to the catalytic converter.
3. Engine misfires and rough idling.
4. Increase in harmful emissions.
5. Risk of engine stalling.
9. Most frequent questions people ask on AutoForums about this fault :
1. Q: What causes the OBD fault code P0171 – System Too Lean –Bank 1?
A: The most common causes of this fault code are a vacuum leak, faulty oxygen sensors, a dirty or clogged Mass Air Flow (MAF) sensor, or a malfunctioning fuel pump.
2. Q: How can I diagnose a lean condition on Bank 1?
A: You can use a scan tool to monitor the fuel trims and oxygen sensor readings, visually inspect for any vacuum leaks, and perform a fuel pressure test to check the fuel delivery system.
3. Q: What are the symptoms of a lean air-fuel mixture on Bank 1?
A: Common symptoms include rough idling, hesitation or stumbling during acceleration, reduced power, and an illuminated check engine light.
4. Q: Can a dirty air filter cause the P0171 fault code?
A: Yes, a clogged or dirty air filter can disrupt the air-fuel mixture and contribute to a lean condition, potentially triggering the P0171 fault code.
5. Q: How can I fix the P0171 fault code on Bank 1?
A: Once the cause is identified, common fixes may include repairing vacuum leaks, replacing faulty oxygen sensors, cleaning or replacing the MAF sensor, or addressing fuel delivery issues such as a clogged fuel filter or a failing fuel pump.
10. Diagnostic cautions and safety measures :
1. Check for any potential vacuum leaks in the intake system.
2. Inspect the air intake system for any restrictions or obstructions.
3. Evaluate the condition of the mass airflow sensor (MAF).
4. Verify the functionality of the oxygen sensor (O2) to ensure its accuracy.
5. Examine the fuel pressure and delivery system for any issues.
6. Check for potential exhaust system leaks or restrictions.
This article was crafted using OBDQuest, the app that demystifies OBDII codes with clear explanations, fixes, and troubleshooting tips. Download OBDQuest from Google Play or the App Store. Subscription is at lowest price right now. Get started today and simplify your car diagnostics.
Fix My OBD2 