Code Definition

P2173 — High Air Flow / Vacuum Leak Detected

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P2173

P2173 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2173 is stored, the module has detected a signal or supply voltage lower than the expected operating range; and a signal or supply voltage higher than the expected operating range.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P2173 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The Powertrain Control Module (PCM) calculates expected engine air flow from mass air flow, manifold pressure, throttle angle, engine speed, and fuel trim, and continuously compares the actual values against that model. DTC P2173 is a generic powertrain code set when the PCM detects higher air flow or manifold pressure than the throttle position and engine speed should produce, together with excessive positive fuel trim correction. This combination indicates unmetered air is entering the engine, most commonly through a vacuum leak or an air leak after the mass air flow sensor. The driver may n...

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