P2173
High Airflow/Vacuum Leak Detected (Slow Accumulation)
Long-term fuel and air adaptation values indicate a slow but continuous excess of air entering the engine. The ECU concludes that an unmetered air leak is gradually growing in the intake system.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Cracked vacuum hose or intake gasketCommon
- Dirty mass airflow sensorPossible
Parts involved
- Intake Manifold Gasket
- Vacuum Hoses
- Throttle Body
- Mass Air Flow Sensor
P2173 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.