P0100 Code: MAF Circuit — Causes & Fix
P0100 means a malfunction in the mass air flow (MAF) sensor circuit — the sensor that measures how much air enters the engine so the ECM can meter fuel.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $30 – $400
- Time to fix
- 30 minutes – 2 hours
What it means
Common causes are a dirty or failed MAF sensor, an unmetered air (vacuum) leak, a loose/corroded connector, or damaged wiring. P0100 is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer petrol car or light truck regardless of make. Fix the underlying fault, then clear the code with an OBD-II scan tool — it will return if the problem isn't resolved.
Symptoms
- Check engine light on
- Rough idle, stalling, or hesitation
- Poor fuel economy and reduced power
How to fix it
- 1
Inspect and clean the MAF sensor
1. Locate the MAF sensor in the intake duct after the air filter. 2. Check the connector and wiring. 3. Clean the sensor element with MAF-specific cleaner (never touch it).
- 2
Check for air leaks
1. Inspect the intake boot and vacuum lines for cracks or loose clamps. 2. Repair leaks, then clear the code and retest.
Frequently asked questions
Can I drive with P0100?
Short trips usually, but the engine may run poorly and use more fuel. Diagnose it soon — a bad air-flow reading makes the ECM fuel incorrectly.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.