p0171
Moderate
Mitsubishi · SUVs
System Too Lean (Bank 1)
Quick Answer
Error code P0171 on your Mitsubishi SUVs means: System Too Lean (Bank 1). This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Check for vacuum leaks around engine hoses
2
Inspect and test oxygen sensors with multimeter
3
Examine fuel pressure regulator and fuel filter
4
Read fuel injector resistance values
5
Perform fuel system pressure test
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
Oxygen sensor
Fuel injectors
Fuel filter
Vacuum hoses
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