Number P2279: Intake Air System Leak (Bank 1)
P2279 means the ECM has concluded that air enters the engine without being measured or expected, for example because the air mass sensor, manifold pressure and throttle position no longer agree with its air model. Volkswagen and Audi use it widely. On the 2013 to 2016 Audi A6, A7 and A8 4.0 TFSI, a
Can you drive with P2279?
Severity: Fix promptly — drivability fault. Short trips at moderate speed only. If the car has entered limp mode (won't rev, stuck in one gear), have it towed rather than forcing it.
If you ignore it: Limp-mode faults tend to strand you, and several of them (misfires, throttle faults) damage other parts while you wait.
This is the #94 most common code in our top-150 library, in the fuel trim & air metering family (Powertrain system). Severity is Number Nest's editorial triage — if the light is flashing or the car feels unsafe, stop driving it whatever any page says.
What P2279 means
P2279 means the ECM has concluded that air enters the engine without being measured or expected, for example because the air mass sensor, manifold pressure and throttle position no longer agree with its air model. Volkswagen and Audi use it widely. On the 2013 to 2016 Audi A6, A7 and A8 4.0 TFSI, a leaking pressure-regulating valve in the crankcase breather module set P2279 with P0507 and a metallic whistle at warm idle; a fabric-reinforced membrane fixed it. On 2.0 TFSI engines (BPY, CCTA and others) a check valve that did not seal under boost let pressure into the crankcase, logging P2279, P2187 and P1297 with oil leaking at the filler cap. For the 2.5 litre five-cylinder Volkswagen advises checking cam timing first, since a timing offset changes the air the engine draws. Diesels set it too: the Mercedes OM651 2.2 in the international Jeep Compass and Patriot logged it with limp mode and got a new air filter and software.
Systems involved: intake manifold, pcv valve, crankcase breather, charge air pipe, mass air flow sensor.
Causes, ranked by likelihood
| # | Cause | Likelihood |
|---|---|---|
| 1 | Leaking crankcase breather or PCV pressure-regulating valve | most likely |
| 2 | Leak at intake manifold, hoses or seals after the air mass sensor | possible |
| 3 | Camshaft timing offset | less common |
| 4 | ECM calibration needing an update | less common |
Check them in order — the list is ranked so the likely, cheaper causes come before the expensive part.
Symptoms you may notice
- Malfunction indicator lamp on
- Whistling at idle, unstable or high idle speed
- Limp mode on some engines
Misdiagnosis traps
- Replacing the part named by the code title without testing. The code reports a failed self-test; the cause list above is ranked so the likely, cheap causes are checked before the expensive part is condemned.
- Clearing the code and declaring victory when the light stays off for a day — the monitor that sets this code runs only under specific driving conditions.
(General diagnostic guidance for this code family — no code-specific trap is published for this code.)
How a good shop confirms it
- Confirm the code and record any companion codes — companions narrow the system fast.
- Inspect the affected components and their wiring/connectors for damage, corrosion and looseness.
- Test the top-ranked cause with live data or a multimeter before replacing anything.
(Standard diagnostic path for this family, labeled as general guidance.)
Repair options & costs
| Repair | Shop total (parts + labor) | DIY (parts only) | Difficulty |
|---|---|---|---|
| Mass air flow (MAF) sensor | $158 – $420 | $120 – $320 (parts only) | 1/5 |
| Intake / vacuum leak repair (gaskets, hoses) | $338 – $838 | $150 – $400 (parts only) | 3/5 |
National ranges from Number Nest's cost model (midsize car, independent shop, US-average labor). Published cross-check — Mass air flow (MAF) sensor: CarMD 2026 national average $346.
OBDex repair data for this code rates the job difficulty medium with a typical labor time in the 0.5–3 hour range and DIY possible: yes.
Price this repair in your state
Estimated total: — (midsize car, independent shop)
Frequently asked questions
How much does it cost to fix P2279?
The fix most associated with this code — mass air flow (maf) sensor — runs $158 – $420 at an independent shop for a midsize car in our cost model (parts + labor, US average). The code names a system, not a part, so confirm the cause before spending: the ranked causes above are ordered by likelihood.
Can I drive with P2279?
See the can-you-drive verdict above — it is based on the system involved and the cascading-damage risk, and it is our editorial triage, not a manufacturer instruction. If the light is flashing or the car feels unsafe, stop driving it regardless of any code.
Will P2279 clear itself?
If the fault was a one-off (a loose cap, a cold-start glitch), the light can go out after several clean trips and the code ages into history. A fault that is still present re-sets the code as soon as the car runs that self-test again — monitors run under specific conditions, which is why "it hasn't come back in two days" is not proof of a fix.
Will my car fail inspection with P2279?
In states with OBD-based emissions inspection, yes — an illuminated check-engine light or an incomplete readiness monitor fails the test regardless of what the tailpipe would show. C-codes (ABS) fall under safety inspection instead in states that have one.
What should I check first for P2279?
The first item on the ranked-causes list above — it is ranked likelihood-first for exactly this reason — plus the free checks: recent work in the area (connectors left loose are a classic), fluid levels, and the battery and grounds on electrical codes.
Where this data comes from
Code facts, causes and symptoms come from OBDex — an open dataset of independently authored descriptions of the standardized generic OBD-II codes (CC0 1.0, public domain; github.com/foerbsnavi/OBDex). The SAE J2012 document itself is copyrighted and is not reproduced here. Cost ranges are Number Nest's own US planning model: national parts and labor ranges cross-checked against the CarMD Vehicle Health Index 2026 published averages, with labor adjustable by the BLS OEWS May 2025 state wage index for auto technicians (occupation 49-3023) — a wage index, not a surveyed shop rate. Severity and can-you-drive notes are our editorial triage, not a manufacturer instruction.