What is po171 code means?

The P0171 code indicates that the engine control module (ECM) has detected a lean fuel mixture in the engine, meaning there is too much air and not enough fuel being delivered for optimal combustion. This can be caused by issues such as a vacuum leak, a malfunctioning mass airflow sensor, or fuel delivery problems. If left unaddressed, a lean condition can lead to poor engine performance, increased emissions, and potential engine damage. It’s important to diagnose and fix the underlying issues to restore proper air-fuel balance.