What are lean codes: P0171 and P0174 indicate a lean fuel mixture on Bank 1 and Bank 2, often detected by upstream oxygen sensors. Why they matter: Lean conditions can cause misfires, hesitation, ...

Let's begin with the basics here: An automotive oxygen sensor is part of the exhaust system and does what its name implies, sensing how much oxygen is in the exhaust gases. And that's important for at ...

Your oxygen (O2) sensors are small but mighty — they help your engine run efficiently, cut emissions, and prevent costly damage. With the right OBD-II scanner and a bit of know-how, you can decode ...