P0171 Fault Code

System Too Lean (Bank 2)

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0171 code indicates that the engine control module (ECM) has detected that the air-fuel mixture is too lean on Bank 2. This condition can lead to poor engine performance, increased emissions, and potential engine damage if not addressed promptly.

What are the symptoms of the P0171 code?

• Poor acceleration and loss of power.
• Rough idling and engine stalling.
• Increased exhaust emissions.
• Check Engine light illuminated on the dashboard.
• Misfiring or abnormal engine noise.

What causes the P0171 code?

• Vacuum leaks in the intake manifold or vacuum hoses.
• Faulty fuel injectors that are not delivering enough fuel.
• Weak fuel pump that fails to provide sufficient fuel pressure.
• Clogged fuel filter restricting fuel flow.
• Malfunctioning mass airflow (MAF) sensor sending incorrect readings.
• Faulty oxygen sensor on Bank 2 misreading the air-fuel mixture.

How to fix P0171?

• Inspect and repair any vacuum leaks in the system.
• Test and replace faulty fuel injectors as necessary.
• Check fuel pump operation and replace if needed.
• Replace a clogged fuel filter to ensure proper fuel flow.
• Clean or replace the MAF sensor if it is malfunctioning.
• Inspect the oxygen sensor on Bank 2 and replace if it is faulty.