Investigating P0100 on Your 2021 Ford Bronco
A P0100 code on your 2021 Ford Bronco means the PCM has detected a malfunction in the mass air flow (MAF) sensor circuit. As the first year of the reborn 6th-generation Bronco, your 2021 model uses the 2.3L EcoBoost I4 or the 2.7L EcoBoost V6, both turbocharged engines that depend on accurate MAF readings.
Broncos frequently see off-road use, dusty trails, and water crossings—all of which can accelerate MAF sensor contamination.
Symptoms
- Check engine light on
- Rough or unstable idle
- Hesitation during acceleration
- Reduced power—noticeable off-road and on climbs
- Poor fuel economy
- Possible stalling
Common Causes
- Contaminated MAF sensor (37%) — Dust, mud, and debris from off-road use. Water crossings can also introduce moisture to the intake. Aftermarket intakes popular on Broncos compound the risk.
- Wiring or connector issues (21%) — Off-road vibration and impacts can loosen connections.
- Faulty MAF sensor (17%) — Internal sensor failure.
- Intake or intercooler piping leak (14%) — Both EcoBoost engines have turbo piping that can loosen from off-road jarring.
- Air filter saturation (7%) — Wet or severely contaminated filter from off-road conditions.
- PCM issue (4%) — Rare.
Diagnostic Steps
- MAF sensor cleaning — Remove and clean with dedicated MAF cleaner spray.
- Air filter inspection — Check for water saturation, mud, or excessive contamination. Replace immediately if wet.
- Intake and turbo piping inspection — Check all connections for looseness from off-road use.
- Connector inspection — Check for mud, moisture, and corrosion.
- Scan tool data — Verify MAF readings with FDRS or compatible scanner.
- MAF replacement — If cleaning doesn't resolve the code.
Repair Costs
- MAF cleaning: $10–$15 (DIY)
- Air filter: $18–$35 (DIY)
- MAF sensor: $140–$340
- Intake boot/piping: $85–$230
- Wiring repair: $95–$280
Warranty
Your 2021 Bronco's basic warranty has expired. The federal emissions warranty covers the MAF sensor for 8 years/80,000 miles through 2029. Check mileage with a Ford dealer.