p0171
Moderate
Peugeot · Sedans & Hatchbacks
System Too Lean (Bank 1)
Quick Answer
Error code P0171 on your Peugeot Sedans & Hatchbacks 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 note trim values
2
Inspect all vacuum hoses for cracks or loose connections
3
Test oxygen sensors with voltage meter
4
Check fuel pressure at fuel rail
5
Clean or replace mass air flow sensor if dirty
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 injector
Mass air flow sensor
Vacuum hoses
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