P2279 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Safe to drive (short-term)
P2279 on a BMW means the ECU sees more air in the cylinders than the MAF measured, so unmetered air is entering downstream of the sensor and pushing fuel trims positive.
- Severity
- Moderate · Emissions
- Typical repair cost, all makes
- €8-€750
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your BMW and Skanyx tells you what P2279 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P2279 mean on a BMW?
The Quick Answer above is the generic definition. What follows is the model-specific detail for the BMW models that log P2279.
BMW 3-Series N54/N55 (E90/E92)
2006-2013
The N54 and N55 in the 3 Series use plastic charge pipes. Mishimoto's engineering page says the factory plastic pipes become brittle and weak after repeated heat cycles, and that a crack lets unfiltered air into the engine. Smoke-test the charge pipe and its connections.
Source: mishimoto.com, en.wikipedia.org
Sources
- mishimoto.com mishimoto.com/engineering/2024/02/charge-forth-performance-charge-pipes-for-bmw-
- en.wikipedia.org en.wikipedia.org/wiki/BMW_N54
What causes P2279 on a BMW?
Beyond the generic causes listed on the main P2279 page, these are the patterns noted for BMW models:
Cracked factory plastic charge pipe or its connections
: BMW 3-Series N54/N55 (E90/E92)
Perished brake booster vacuum hose at the check valve
: BMW 3-Series N54/N55 (E90/E92)
How to diagnose P2279 on a BMW with OBD2
- Scan for all stored codes. P2279 usually shows up with P0171 and/or P0174, which confirm the lean condition.
- Read live fuel trims at idle and at 2500 rpm. Long-term trim strongly positive at idle but close to zero at higher rpm points to a small vacuum leak, because a fixed amount of unmetered air matters far less once total airflow rises.
- Visually inspect the intake boot, flexing it and checking the underside where cracks often hide, plus the clamps at the MAF and throttle body.
- Pull the oil filler cap at idle. If idle changes sharply or the cap sucks down hard, the PCV system needs attention.
- Smoke test the intake tract with an EVAP smoke machine at 0.5 psi (0.035 bar). Escaping smoke pinpoints the leak in minutes.
- With the engine idling, spray carb cleaner or feed propane around suspect joints. An rpm change confirms leak location.
- Inspect intake manifold seams, vacuum ports, and the brake booster hose for cracks, especially on plastic manifolds past 150,000 km.
- Clear the code, drive a full warm-up cycle, and recheck fuel trims to confirm the repair took.
How much does P2279 cost to fix on a BMW? (EUR)
Estimated repair costs for P2279 in EUR, compiled across makes. Expect BMW parts and labour towards the upper end of each range.
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Replace cracked intake boot or hose | €25–€90 | €30–€80 | €55–€170 | Easy |
| Replace PCV valve and associated hoses | €15–€120 | €40–€150 | €55–€270 | Easy |
| Replace intake manifold gasket | €40–€150 | €250–€600 | €290–€750 | Professional |
| Replace vacuum lines or brake booster hose | €10–€60 | €40–€120 | €50–€180 | Easy |
| Replace throttle body gasket | €15–€50 | €80–€180 | €95–€230 | Moderate |
| Replace a missing or damaged oil filler cap | €8–€30 | €0–€20 | €8–€50 | Easy |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P2279
These codes are often seen alongside P2279 or point to related issues, on any make:
Looking for the full P2279 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P2279 guide