Investigating the P0100 Code on Your 2022 Subaru Impreza
A P0100 code on your 2022 Subaru Impreza means the ECM has detected a malfunction in the Mass Air Flow (MAF) sensor circuit. Your 5th-generation Impreza's 2.0L boxer engine depends on precise MAF data for fuel delivery and CVT management. With the basic warranty potentially expired, check your emissions warranty status first.
MAF Sensor on the 2022 Impreza
The FB20D 2.0L boxer four-cylinder (152 hp) uses a hot-wire MAF sensor. After three-plus years, PCV oil vapor can contaminate the sensing element. The 2.0L's lower airflow range makes it sensitive to minor contamination. The ECM uses MAF data for fuel injection, timing, and Lineartronic CVT coordination.
Symptoms
- Check engine light on with P0100
- Hesitation during acceleration
- Rough idle
- Fuel economy below the 28-36 mpg range
- CVT may shift erratically
- AWD behavior may change
Ranked Causes
- Contaminated MAF sensor element (35-40%) — PCV oil vapor deposits after three-plus years.
- Air intake leak (20-25%) — Loose connection or cracked hose.
- MAF sensor failure (15-20%) — Internal electronics degradation.
- Wiring or connector issue (10-15%) — Corrosion or damage.
- Air filter condition (5-10%) — Neglected filter.
Diagnosis and Repair
- Check warranty — Basic warranty (3yr/36k) may have expired. Emissions warranty (8yr/80k) covers through 2030.
- Scan codes — Confirm P0100.
- Inspect intake — Check filter, hose, clamps, housing.
- Clean MAF sensor — Remove and spray with MAF cleaner ($10-15).
- Monitor data — Compare readings against FB20D specifications.
Repair Costs
- Under emissions warranty: $0 if eligible
- MAF sensor cleaning: $10-15 (DIY)
- MAF sensor replacement: $100-230 parts, $50-100 labor
- Intake hose: $25-70
- Wiring repair: $80-200