BMW P0171 Code – System Too Lean Bank 1
Limited
Safe to drive :
BMW vehicles only
Applies only to :
Not applicable to :
This explanation does NOT apply to Ford, Toyota, GM, VW, or other manufacturers.
Medium
Severity level :
When Does This Code Appear on the Vehicles
BMW P0171 commonly appears with rough idle, hesitation, or lean running symptoms, especially after cold start.
What This Code means on the Vehicles
On BMW vehicles, P0171 indicates Bank 1 fuel mixture is too lean beyond DME correction limits.
Why This is different from a generic OBD2 Code
BMW engines are extremely sensitive to unmetered air, and lean codes are far more likely caused by intake or crankcase ventilation leaks than fuel pump failure.
Common Situations That Trigger This Code
Cracked intake boots; Failed CCV system; Vacuum leaks; Aging MAF sensor.
What Will NOT Fix This Code
Replacing oxygen sensors without smoke testing; Replacing catalytic converters.
How to Clear This Code on Vehicles
Perform smoke test on intake system, inspect CCV, verify fuel trims, then clear code.
Related Manufacturer Specific Codes
BMW P0174; BMW P1130