P0102 - Mass or Volume Air Flow Circuit Low Input

MAF signal voltage/reading is too low.

Treat the code as the starting point: compare symptoms, likely causes, and repair paths before pricing parts or moving into an estimate.

Code Overview

MAF signal voltage/reading is too low.

Common Causes

• Unplugged or failing mass air flow sensor
• Wiring open or short to ground in the MAF circuit
• Air intake restriction reducing measured airflow
• Unmetered air leak skewing the signal

Symptoms

• Hesitation or weak throttle response
• Rough idle or lean stumble
• Poor fuel economy or reduced power

Diagnostic Steps

1. Make sure the MAF connector is fully seated and the terminals are clean
2. Inspect the harness for opens, rubbed-through spots, or poor ground
3. Check the air filter and intake ducting for restriction or collapse
4. Compare MAF data to expected airflow at idle and snap throttle

Repair Difficulty

Moderate

General difficulty estimate for the most common repair path.

Likely Repairs & Cost Guides

Use symptoms, scan data, and quick checks to confirm the likely repair path before pricing parts. The estimator helps compare repair paths before replacing anything unnecessarily.

Related OBD Codes

Browse nearby code-family pages when the same fault pattern overlaps across systems, such as misfire, lean fuel trim, EVAP sealing, cooling, or charging faults.

Next Steps

Move from code lookup to diagnosis, then estimate the likely repair only after symptoms, causes, and checks point to the same path.