P0100 on Your 2023 Toyota Sienna
A P0100 code on your 2023 Toyota Sienna indicates the ECM has detected a malfunction in the mass air flow (MAF) sensor circuit. The Sienna is hybrid-only, using a 2.5L Atkinson-cycle engine with electric motors. This code is relatively uncommon on a newer vehicle.
Symptoms
- Check engine light on
- Rough idle when gas engine runs
- Hesitation during acceleration
- Reduced fuel economy
- Gas engine engaging more often
- Possible stalling
Common Causes
- Contaminated MAF sensor (30%) — Oil or debris from service contamination or an aftermarket oiled filter.
- MAF connector issue (25%) — Connection not fully seated or vibrated loose.
- Faulty MAF sensor (20%) — Early sensor failure.
- Intake assembly issue (12%) — Loose clamp or boot.
- Software calibration (8%) — ECM may need software update.
- Wiring issue (5%) — Defect or damage.
What to Do
- Check warranty — Toyota's 3-year/36,000-mile warranty extends through 2026.
- Dealer visit — Likely covered at no cost.
- Document symptoms — Note when the issue occurs.
Repair Costs
- Under warranty: $0
- MAF cleaning (if out of warranty): $10–$15 (DIY)
- MAF sensor: $130–$310
Warranty
Your 2023 Sienna is covered under Toyota's 3-year/36,000-mile warranty through 2026 and the federal emissions warranty for 8 years/80,000 miles through 2031.