P2ADF: Intake Air System Leak Bank 2

What it means

The ECM detects a leak in the intake air system on bank 2. Air entering downstream of the MAF sensor causes lean fuel trim and unmetered air ingress.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The intake system carries air to the engine, and the mass airflow sensor measures incoming air so fueling can be matched to it. This code identifies a leak on bank 2, where air entering downstream of the MAF can bypass measurement and make that bank run lean.

Common causes

Most likely first.

1. Cracked intake hose between MAF and throttle
2. Intake manifold gasket leaking

Symptoms

• Check-engine light may be on
• Rough or high idle
• Hesitation or reduced power

How to diagnose it

1. Check freeze-frame data and bank-specific fuel trims at idle and raised engine speed for evidence of unmetered air on bank 2.
2. Inspect intake hoses downstream of the MAF for cracks, loose clamps, and disconnected branches leading to bank 2.
3. Check the bank 2 intake manifold area and gasket for signs of a leak, such as a damaged seal or a change in idle when the area is safely inspected.
4. Use an appropriate smoke test to locate air entering the bank 2 intake downstream of the MAF.
5. After repairing any leak, clear the code and confirm bank 2 fuel trims and idle behavior improve.

Common fixes

• Re-seat and tighten a loose intake hose or clamp downstream of the MAF.
• Replace a cracked intake hose that allows unmetered air into bank 2.
• Replace a leaking bank 2 intake manifold gasket.
• Clear the code and verify that bank 2 fuel trims return toward normal.

Can I keep driving?

If the engine is running smoothly, a short drive to arrange repair may be possible, but avoid hard acceleration and long trips. A continuing bank 2 air leak can cause rough or high idle, hesitation, poor fuel economy, and increased emissions.