p0171
Moderate
Cadillac · Sedans
System Too Lean (Bank 1)
Quick Answer
Error code P0171 on your Cadillac Sedans 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 OBD2 scanner to diagnose exact error
2
Check oxygen sensors for proper operation
3
Inspect fuel injectors and clean if necessary
4
Test fuel pressure and regulator
5
Verify mass air flow sensor operation
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
Fuel filter
Vacuum hose
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