p0171
Moderate
Subaru · SUVs & Crossovers
System Too Lean (Bank 1)
Quick Answer
Error code P0171 on your Subaru SUVs & Crossovers means: System Too Lean (Bank 1). This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Connect OBD-II scanner and confirm P0171
2
Check fuel pressure at fuel rail (should be 40-50 PSI)
3
Inspect oxygen sensors for proper operation
4
Check for vacuum leaks using smoke tester
5
Verify fuel injector operation with multimeter
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
OBD-II scanner
Fuel pressure gauge
Oxygen sensor
Fuel filter
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