What does P0102 mean?
The mass airflow (MAF) sensor sits in the intake after the air filter and measures how much air the engine is pulling in. The computer uses that number to work out how much fuel to inject.
The computer is seeing a signal voltage that is lower than the sensor should ever produce, so it is almost always an electrical problem rather than a mechanical one.
Codes are a starting point. They tell you which test failed, not which part to replace. Check for other stored codes and fix those in a sensible order.
Symptoms
- Check engine light
- Hesitation or stalling
- Rough idle
- Poor fuel economy
- Black smoke on some diesels
Common causes
- Open in the 5 V reference wire
- Signal wire shorted to ground
- Unplugged or corroded connector
- Failed sensor
How to diagnose P0102
- With the key on, back-probe the connector: you should see about 5 V on the reference wire and a good ground (under 0.1 V drop).
- If reference and ground are good, check the signal wire for a short to ground with the connector unplugged.
- If the wiring checks out, the sensor itself is the likely fault.
- Inspect the air filter and intake boot for cracks or loose clamps.
- Check MAF readings in live data. At warm idle, many engines read roughly 2 to 7 grams per second (bigger engines higher).
How to fix it
- Clean the MAF sensor
- Repair intake leaks
- Replace the air filter
- Repair wiring
- Replace the MAF sensor
Estimated repair cost
Likely repairs for P0102 run from about $20 to $450, depending on the cause.
| Repair | Typical range (parts + labor) |
|---|---|
| Diagnostic fee (scan + testing) | $100 - $200 |
| MAF sensor cleaning | $20 - $100 |
| Mass airflow sensor replacement | $150 - $450 |
| Vacuum leak repair (hose/gasket) | $100 - $450 |
These are rough US estimates for an independent shop in 2026, based on typical parts prices and standard labor times. Dealers, big trucks, luxury brands and high-cost areas often run higher. They are not quotes. Use the repair cost estimator to adjust for your vehicle.
How serious is P0102?
Moderate severity
Usually drivable, but hesitation and stalling can be a safety issue in traffic.
P0102 FAQ
What does P0102 mean?
P0102 stands for "Mass or Volume Air Flow Sensor "A" Circuit Low". The mass airflow (MAF) sensor sits in the intake after the air filter and measures how much air the engine is pulling in.
Can I drive with a P0102 code?
Usually drivable, but hesitation and stalling can be a safety issue in traffic.
How much does it cost to fix P0102?
It depends on the cause. The likely repairs for P0102 range from about $20 to $450 at an independent shop in the US, plus a diagnostic fee of roughly $100-$200. These are rough estimates; dealer prices and some vehicles run higher.
What is the most common cause of P0102?
The most common causes are: open in the 5 V reference wire; signal wire shorted to ground; unplugged or corroded connector.