What does P0100 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 has detected an electrical fault in the sensor circuit.
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 or shorted wiring
- Corroded or loose connector
- Failed sensor
- Blown fuse or reference voltage issue shared with other sensors
How to diagnose P0100
- Look for other codes that share the same 5 V reference circuit.
- Inspect the connector and wiring, then check reference, ground and signal voltages.
- Replace the sensor only after the wiring tests good.
- 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 P0100 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 P0100?
Moderate severity
Usually drivable, but hesitation and stalling can be a safety issue in traffic.
P0100 FAQ
What does P0100 mean?
P0100 stands for "Mass or Volume Air Flow Sensor "A" Circuit". 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 P0100 code?
Usually drivable, but hesitation and stalling can be a safety issue in traffic.
How much does it cost to fix P0100?
It depends on the cause. The likely repairs for P0100 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 P0100?
The most common causes are: open or shorted wiring; corroded or loose connector; failed sensor.