Toyota 4Runner P0174 Lean Code | Full Diagnosis & Repair (2003–2009)

In this video, I diagnose and repair a 2005 Toyota 4Runner (4th Gen) that came in with a P0174 trouble code (System Too Lean – Bank 2). Rather than replacing parts blindly, I walk through the full diagnostic process to determine what was actually causing the lean condition. After checking fuel trims, intake air data, and live sensor readings, I traced the issue back to a faulty Mass Air Flow (MAF) sensor. This video covers: What P0174 means on a Toyota 4Runner How to diagnose a lean condition correctly Checking short-term and long-term fuel trims How a bad MAF sensor causes lean codes Replacing the MAF sensor Clearing codes and verifying the repair After replacing the MAF sensor, the fuel trims returned to normal and the P0174 code did not return. This diagnostic process applies to all Toyota 4Runner models from 2003–2009 equipped with the 1GR-FE V6, and is helpful for anyone dealing with lean codes, hesitation, or poor drivability. 🔧 If your 4Runner has a lean code and runs rough, this video will help you understand the correct fix. ✋ Make sure to Like & Subscribe to Red Beard Auto Hub for more real-world diagnostic and repair videos! Filmed by Novo Motorworks — Mobile Auto Repair · Los Angeles, CA We bring the shop to you! From diagnostics to full repairs, Novo Motorworks provides professional mobile automotive service across the Los Angeles area. 📍 Serving: Greater Los Angeles & Near Area 📸 Instagram: @NovoMotorworks 🏷️ Hashtags #Toyota4Runner #4thGen4Runner #P0174 #LeanCondition #MAFSensor #ToyotaDiagnosis #ToyotaRepair #CarDiagnosis #DIYCarRepair #RedBeardAutoHub #NovoMotorworks