P0103 – Mass or Volume Air flow Circuit High Input
What does P0103 mean?
The mass air flow sensor is reporting a signal higher than the expected range — the computer is being told more air is entering the engine than is physically plausible. This is the opposite condition to P0102.
What causes P0103?
Listed from most to least common:
- 1Failed MAF sensor
- 2Short circuit in the MAF signal wiring
- 3Contaminated sensor element reading incorrectly
- 4Poor ground connection to the sensor
- 5Damaged connector
Code breakdown
Common symptoms
- Check engine light on
- Black smoke from the exhaust
- Strong fuel smell
- Rough running and poor idle
- Significantly worse fuel economy
How to diagnose
- 1Inspect the MAF connector and wiring for damage, chafing, or shorts to power.
- 2Clean the sensor element and re-test.
- 3Compare live MAF readings against specification — implausibly high values at idle confirm the fault.
- 4Check the sensor's ground circuit for integrity.
- 5Substitute a known-good sensor if available before purchasing.
The computer will add fuel to match the false high airflow reading, causing a rich condition that wastes fuel and can foul plugs and damage the converter.
Common fixes and estimated costs
| Repair | Estimated cost |
|---|---|
| Clean MAF sensor | $10–$30 (DIY) |
| Repair wiring or connector | $80–$300 |
| Replace MAF sensor | $150–$400 |
Costs are rough US estimates including parts and labor. Actual pricing varies significantly by vehicle, region, and shop rates.
Good to know
A short to voltage in the signal wire produces the same symptom as a failed sensor. Check the wiring before replacing the part, especially if the harness runs near hot or moving components.
Related codes
This information is provided for general reference only and may vary by manufacturer, model, and year. It is not a substitute for professional diagnosis or repair.