P0100 on Your 2021 Honda Pilot
A P0100 code on your 2021 Honda Pilot means the ECM has detected a malfunction in the mass air flow (MAF) sensor circuit. Your 3rd-generation Pilot uses the 3.5L V6 engine, which depends on accurate MAF readings for proper fuel metering across all six cylinders.
Symptoms
- Check engine light on
- Rough or hunting idle
- Hesitation during acceleration
- Reduced power—noticeable when loaded
- Poor fuel economy
- Possible stalling at low RPM
Common Causes
- Contaminated MAF sensor (35%) — Oil, dirt, or debris coating the sensing element. Aftermarket oiled air filters are a common contributor.
- Wiring or connector issues (22%) — Four-plus years of heat and vibration can loosen connections or corrode pins.
- Faulty MAF sensor (18%) — Internal sensor failure.
- Intake air leak (13%) — Cracked boot or loose clamp allowing unmetered air past the sensor.
- Air filter restriction (7%) — Clogged or overdue filter.
- ECM issue (5%) — Rare fault.
Diagnostic Steps
- MAF sensor cleaning — Remove and clean with dedicated MAF cleaner spray.
- Connector inspection — Check for corrosion, loose fit, or bent pins.
- Air filter check — Replace if dirty or switch from oiled to paper filter.
- Intake inspection — Check all post-MAF connections for leaks.
- Scan tool verification — Confirm MAF readings are within spec.
- MAF replacement — If readings remain abnormal.
Repair Costs
- MAF cleaning: $10–$15 (DIY)
- Air filter: $15–$28 (DIY)
- MAF sensor: $145–$345
- Intake boot: $75–$195
- Wiring repair: $95–$275
Warranty
Your 2021 Pilot's basic warranty has expired. The federal emissions warranty covers the MAF sensor for 8 years/80,000 miles through 2029. You likely still qualify—check mileage with your Honda dealer.