Investigating P0100 on Your 2021 Honda CR-V
A P0100 code on your 2021 Honda CR-V means the ECM has uncovered a malfunction in the mass air flow (MAF) sensor circuit. After four-plus years of service, MAF contamination and connection issues become increasingly common clues to investigate.
Your 5th-generation CR-V uses the 1.5L turbocharged engine (or the 2.0L hybrid in CR-V Hybrid trims), both relying on precise airflow measurement for optimal engine performance.
Symptoms
- Check engine light on
- Rough or hunting idle
- Hesitation during acceleration
- Reduced power and sluggish response
- Poor fuel economy
- Possible stalling at low RPM
Common Causes
- Contaminated MAF sensor (36%) — Oil, dirt, and debris accumulate on the sensing element over time. Aftermarket oiled air filters accelerate contamination.
- Wiring or connector degradation (22%) — Four years of heat cycling and engine 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. The 1.5T's intercooler piping is a potential leak point.
- Air filter restriction (7%) — Clogged or overdue filter.
- ECM issue (4%) — Rare at this age.
Diagnostic Steps
- MAF sensor cleaning — Remove and clean with dedicated MAF cleaner spray. Most cost-effective first step.
- Connector inspection — Check for corrosion, bent pins, or looseness.
- Air filter replacement — Install a fresh OEM-style paper filter.
- Intake inspection — Check all connections between the air filter box and throttle body, including intercooler piping.
- Scan tool verification — Confirm MAF values return to proper range.
- MAF replacement — If readings remain abnormal after cleaning.
Repair Costs
- MAF cleaning: $10–$15 (DIY)
- Air filter: $15–$28 (DIY)
- MAF sensor: $145–$335
- Intake boot/piping: $80–$200
- Wiring repair: $95–$270
Warranty
Your 2021 CR-V's basic warranty has expired. However, the federal emissions warranty covers the MAF sensor for 8 years/80,000 miles through 2029. Check your mileage with a Honda dealer—you likely still qualify for covered repair.