P2ADF means the engine control module has concluded that air reaches the cylinders of bank 2 without passing the air measurement. Audi documents the code for the 4.0 litre TFSI V8 in the A8, S8, SQ7, SQ8, RS Q8, RS 6 Avant and RS 7 from model years 2019 to 2023. Drivers notice the check engine or exhaust warning lamp and a whistle from the engine bay; misfire codes for bank 1 and P2279 for bank 1 can be stored alongside. Audi's remedy is a new full-load crankcase breather line serving bank 2, while the oil separators and part-load lines stay in place. On other engines, split intake or boost hoses, leaking manifold gaskets and a stuck crankcase ventilation valve are the usual leak points. P2279 covers the same check for bank 1.
Medium severity. Can I keep driving?You can drive in moderation. Get it repaired soon, because a loose flap can cause major damage on some engines.
Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.
Symptoms
- Check engine or exhaust warning light on
- Whistling noise from the engine bay
- Rough idle or misfire codes
Most likely causes
- Leaking full-load crankcase breather line on bank 2 (Audi 4.0 TFSI)
- Split intake or boost hose on bank 2
- Leaking intake manifold gasket on bank 2
- Crankcase ventilation valve not sealing
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2ADF means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- A: Hybrid or air and fuel
- DF: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2ADF?
You can drive in moderation. Get it repaired soon, because a loose flap can cause major damage on some engines.
What causes code P2ADF?
The most common causes are: leaking full-load crankcase breather line on bank 2 (Audi 4.0 TFSI); split intake or boost hose on bank 2; leaking intake manifold gasket on bank 2.
Related codes
- P2279Intake Air System Leak (Bank 1)
- P0174System Too Lean Bank 2
- P2189System Too Lean at Idle (Bank 2)
- P0507Idle Control System RPM - Higher Than Expected
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.