2015 Hyundai Santa Fe P0171, P0174, and P2096 Codes: Diagnosis After O2 Sensor Replacement
Hello, I'm experiencing persistent engine trouble codes P0171 (System Too Lean Bank 1), P0174 (System Too Lean Bank 2), and P2096 (Post-Catalyst Fuel Trim System Too Lean Bank 1) on my 2015 Hyundai Santa Fe. I've already replaced both O2 sensors, but the codes remain. The issue appears to be a lean mixture in both fuel banks, with post-catalyst feedback indicating ongoing inefficiency. I'm looking for help identifying the root cause. I’ve searched for the Mass Air Flow (MAF) sensor but haven’t found it in any of the available videos or diagrams. While I’m not a professional mechanic, I am comfortable performing basic diagnostics and maintenance tasks. Any insights into potential causes—such as vacuum leaks, faulty MAF sensor, clogged fuel filter, cracked hoses, or PCV valve issues—would be greatly appreciated.
Using a scan tool to monitor live engine parameters makes troubleshooting much more effective. Code P0171 may indicate one or more of the following: - The Mass Air Flow (MAF) sensor is dirty, faulty, or improperly calibrated - A vacuum leak downstream of the MAF sensor - Cracked or loose vacuum lines, including PCV hoses or connections - A stuck-open Positive Crankcase Ventilation (PCV) valve - Faulty or failing oxygen sensors (Bank 1, Sensor 1) - Sticking, plugged, or malfunctioning fuel injectors - Low fuel pressure—possibly due to a clogged or dirty fuel filter - Exhaust leak between the engine and the first oxygen sensor For more detailed information, refer to: p0171