What Does P0174 Mean on Your 2022 Subaru Forester?
A P0174 code on your 2022 Subaru Forester indicates the ECM detected a lean air-fuel mixture on Bank 2. The 2022 Forester uses a 2.5-liter flat-four boxer engine producing 182 horsepower paired with a CVT (Lineartronic) transmission. The horizontally opposed cylinder layout creates two distinct banks, making P0174 a clear indicator of a Bank 2 lean condition.
Your 2022 Forester may still be under Subaru warranty. Check your mileage and purchase date before paying for repairs out of pocket.
Common Symptoms You May Notice
- Check engine light on
- Rough idle
- Hesitation during acceleration
- Decreased fuel economy
- Engine vibration
- Power loss on hills
Most Likely Causes of P0174 on the 2022 Forester
- Vacuum Leak on Bank 2 - Cracked hoses or leaking intake gaskets on the Bank 2 side of the boxer engine.
- Dirty MAF Sensor - Contamination causing underreported airflow.
- Failing Bank 2 O2 Sensor - Degrading sensor providing inaccurate readings.
- Fuel Delivery Issue - Weak pump or restricted fuel flow.
How to Diagnose the Problem
- Scan codes - Confirm P0174 and check for P0171.
- Monitor fuel trims - Compare both banks.
- Inspect vacuum system - Focus on Bank 2 connections.
- Clean MAF sensor - Quick first step.
- Test fuel pressure - Compare to specifications.
Repair Options and Cost Breakdown
- Warranty repair - $0 if covered.
- Vacuum hose repair - $10 to $35.
- MAF sensor cleaning - $8 to $15.
- MAF sensor replacement - $90 to $200, plus $50 to $100 labor.
- O2 sensor replacement - $90 to $230, plus $80 to $160 labor.
- Fuel pump replacement - $230 to $420, plus $160 to $300 labor.
Can You Fix This Yourself?
MAF cleaning and vacuum hose inspection are easy DIY tasks. The boxer engine layout can make O2 sensor access trickier from above, but it is still manageable with the right tools. If your warranty applies, let the dealer handle it.
Prevention Tips
- Replace air filter regularly
- Use quality fuel
- Inspect vacuum connections during maintenance
- Follow Subaru maintenance schedule
- Clean MAF sensor periodically