P0100 on Your 2022 Toyota 4Runner
A P0100 code on your 2022 Toyota 4Runner means the ECM has detected a malfunction in the mass air flow (MAF) sensor circuit. Your 5th-generation 4Runner uses the 4.0L V6—a proven, straightforward engine that relies on the MAF sensor for fuel metering.
Symptoms
- Check engine light on
- Rough or unstable idle
- Hesitation during acceleration
- Reduced power
- Poor fuel economy
- Possible stalling
Common Causes
- Contaminated MAF sensor (35%) — Oil, dust, and debris accumulation. Off-road use accelerates contamination.
- Wiring or connector issues (22%) — Three-plus years of heat and vibration.
- Faulty MAF sensor (18%) — Internal sensor failure.
- Intake air leak (13%) — Cracked boot or loose clamp.
- Air filter restriction (8%) — Overdue replacement.
- ECM issue (4%) — Rare.
Diagnostic Steps
- MAF sensor cleaning — Remove and clean with dedicated MAF cleaner spray.
- Air filter check — Replace if dirty.
- Connector inspection — Check for dirt, corrosion, or looseness.
- Intake inspection — Check all post-MAF connections.
- Scan tool data — Verify MAF readings.
- MAF replacement — If cleaning doesn't resolve it.
Repair Costs
- MAF cleaning: $10–$15 (DIY)
- Air filter: $15–$30 (DIY)
- MAF sensor: $140–$330
- Intake boot: $70–$190
- Wiring repair: $90–$265
Warranty
Your 2022 4Runner's 3-year/36,000-mile warranty extends through 2025. The federal emissions warranty covers the MAF sensor for 8 years/80,000 miles through 2030.