P0102 on BMW: How to Diagnose & Fix
Mass or Volume Air Flow Sensor Circuit Low Input
1 BMW model · 1 documented issue · $300-$900 repair
P0102 on BMW by model: symptoms, diagnosis and fix
The S62 uses dual mass-airflow sensors, and aging or contaminated MAFs are a recurring E39 M5 issue. Owners commonly report rough idle, hesitation, poor throttle response, reduced power, and check-engine lights with mixture adaptation faults. BMW service literature and independent repair databases frequently reference diagnosis of intake leaks versus faulty MAF readings on E39 V8 applications.
Common Symptoms
- Check engine light
- Rough idle
- Hesitation on acceleration
- Reduced engine power
- Poor fuel economy
- Lean mixture faults
How to Fix
Scan for fuel-trim and MAF-related faults, inspect for intake leaks first, then compare live airflow values bank-to-bank. If readings are implausible or one bank differs significantly, replace the affected MAF sensor(s) with OE-quality parts and clear adaptations; also inspect intake boots and air filter condition.
Sources for this issue (2)
- BMW M5 (E39) PH Buying Guide - Powertrainbuying-guide
- Mass Air Sensors for BMW E39 M5 S62 (Turner Motorsport)parts-reference
P0102 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0102 mean on a BMW?
P0102 stands for "Mass or Volume Air Flow Sensor Circuit Low Input." P0102 is a generic OBD-II code meaning the engine computer detected an abnormally low voltage or signal from the Mass Air Flow (MAF) sensor circuit. The MAF sensor measures how much air is entering the engine so the computer can deliver the correct amount of fuel. A low signal tells the computer it is reading less airflow than is actually present, which can cause poor running, stalling, or reduced power. While not usually an emergency, it can affect drivability and fuel economy and should be addressed. On BMW it is documented across 1 model: M5.
What are the most common causes of P0102?
The most common causes of P0102 are: Dirty or contaminated MAF sensor element, Faulty MAF sensor, Damaged, corroded, or loose MAF connector/wiring, Open or short to ground in the signal or power circuit, Dirty or restricted air filter / intake blockage, Vacuum or intake air leak after the sensor, Poor power or ground supply to the sensor. The specific cause varies by vehicle.
How much does it cost to fix P0102 on a BMW?
Published repair estimates on BMW range from $300 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.