2001 Ford Focus SOHC Vehicle with P0136, P0171, and P0000 OBD2 Diagnostic Codes - Solutions and Fixes

Model: 2001 Ford Focus Fault Code: P0171 Posted: 2014-11-15 20:20

I'm experiencing persistent Check Engine Light (CEL) errors on my 2001 Ford Focus with SOHC engine configuration, specifically receiving diagnostic trouble codes P0136, P0171, and P0000. I have already replaced both oxygen sensors and the rubber elbows in the PVC (Positive Crankcase Ventilation) system. The engine runs smoothly under normal conditions, but these codes persist. I'm seeking help to identify the root cause of these issues, especially since P0000 is a rare code that may indicate a serious sensor or wiring problem.