P0102 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Safe to drive (short-term)
P0102 on a BMW means the mass air flow sensor is reporting a voltage or frequency below the expected idle minimum. The ECU thinks almost no air is entering the engine, so it cuts fuel injection accordingly. The root cause is usually a contaminated MAF element, a major air leak after the sensor, or a wiring fault.
- Severity
- Moderate · Fuel System
- Typical repair cost, all makes
- €8-€350
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your BMW and Skanyx tells you what P0102 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 P0102 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 P0102.
BMW 3 Series
2006-2024
Among the 3 Series petrol engines, the naturally aspirated N52 uses a Bosch hot-film MAF, and the N55 also carries one, although it calculates air mass mainly from manifold pressure. The N54 twin-turbo has no MAF at all, so P0102 on a 335i with the N54 cannot come from a MAF. On cars that do have one, oil mist from the crankcase ventilation can coat the element and pull its reading down, so check the connector, wiring and element before replacing the sensor.
Source: cobbtuning.atlassian.net
Sources
- cobbtuning.atlassian.net cobbtuning.atlassian.net/wiki/spaces/PRS/pages/828866941/BMW+N55+Tuning+Guide
What causes P0102 on a BMW?
Beyond the generic causes listed on the main P0102 page, these are the patterns noted for BMW models:
Hot-film MAF element contaminated by crankcase oil mist on the N52
: BMW 3 Series
Corroded or loose MAF connector or damaged signal wire
: BMW 3 Series
How to diagnose P0102 on a BMW with OBD2
- Read live data and check MAF reading at idle. A 4-cylinder should show 2-7 g/s. Below 1 g/s is consistent with P0102
- Inspect the air filter and replace if dirty (a clogged filter pushes MAF readings low)
- Inspect the intake tract from the MAF housing to the throttle body or turbo for cracks, loose clamps, or disconnected hoses
- Clean the MAF sensor using a dedicated MAF cleaner spray (never use brake cleaner or carb cleaner)
- If readings remain low after cleaning and the intake is sealed, unplug the MAF and test drive. If the car runs better, replace the sensor
How much does P0102 cost to fix on a BMW? (EUR)
Estimated repair costs for P0102 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 |
|---|---|---|---|---|
| Clean MAF sensor with MAF-specific cleaner | €8–€20 | €0–€60 | €8–€80 | Easy |
| Replace MAF sensor | €40–€250 | €30–€80 | €70–€330 | Easy |
| Repair intake boot or charge pipe air leak | €20–€150 | €60–€200 | €80–€350 | Moderate |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P0102
These codes are often seen alongside P0102 or point to related issues, on any make:
Looking for the full P0102 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P0102 guide