P0171
System
Powertrain (Fuel/Air)
Scanner som krävs
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

System Too Lean (Bank 1)

Understand P0171, common causes, and the right FOXWELL scanner to diagnose it.

The engine is receiving too much air or too little fuel on bank 1. The ECU cannot trim fuel enough to maintain the target air-fuel ratio.

Vanliga symptom

  • Rough idle
  • Hesitation
  • Long crank times
  • Lean codes may appear with P0174

Typiska orsaker

  • Vacuum leak (intake boot, PCV, brake booster hose)
  • Dirty or failing MAF sensor
  • Weak fuel pump or clogged filter
  • Leaking intake manifold gasket
  • Faulty O2 sensor giving false readings

Vilken scanner behöver du?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Använd live-data och freeze frame innan du byter delar. ABS-, SRS- och U-koder kräver oftast en fullsystems-scanner.

Diagnostiktips

  • Spara freeze frame när koden först sätts
  • Rensa koden först efter att orsaken är åtgärdad
  • Kontrollera relaterade väntande koder
  • Verifiera batterispänning över 12,4 V innan du misstänker sensorer

Rekommenderade FOXWELL-scannrar

Vanliga frågor

Can I diagnose P0171 with a basic code reader?
P0171 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0171?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.