P2ADF: Intake Air System Leak Bank 2
What to do
Expect reduced power under acceleration with normal behaviour at idle, and possibly a whistle or hiss when accelerating hard. Look for a disconnected or split hose between the turbocharger and the engine — on a boosted engine these are pushed apart by pressure rather than sucked together, so a clamp that has loosened is a common and cheap find.
What this code means
An air leak has been detected in the intake system on bank 2.
On a turbocharged engine an intake leak is a different problem from the vacuum leak petrol practice teaches, and confusing them wastes a lot of time.
A naturally aspirated engine has intake pressure below atmospheric, so a hole draws air in — unmetered, past the airflow sensor, leaning the mixture. A turbocharged engine after the compressor is above atmospheric, so the same hole blows air out. Air that was measured on the way in never reaches the cylinder.
Which inverts the symptom. A boost leak does not lean the mixture; it makes the engine run rich, because fuelling was calculated for air that has since escaped. And it costs boost, so the car is down on power under load while behaving normally at idle — the exact opposite of a classic vacuum leak, which is worst at idle and disappears under load.
That load-dependence is the diagnostic. A leak that is invisible at idle and obvious at full throttle is after the compressor; one that is obvious at idle and clears under load is before it.
Bank 2 specifically points at a V engine with twin turbochargers or a split intake path, so the leak is on one side and the other side's readings are the reference that found it.
Likely causes
Start here
- Boost leak in charge pipework · specialist
Less common
- Disconnected or leaking vacuum hose · moderate
- Leaking intake manifold gasket · specialist
Rare
- Corroded or loose connector · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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