If that air-fuel ratio is out of balance, you’ll either notice that something is off, or your car’s computer will detect it first. This mixture ratio is pretty precise, so if it’s off even by a small amount, you could experience the symptoms caused under a P0171 engine code. Bank 1 is where cylinder number 1 is located, and where you’ll find the cause of the code.įor your car to run the way you would expect it to, its engine needs a certain amount of air and a certain amount of fuel. This can be caused by something like a disconnected hose or vacuum leak, which means there’s more air than usual, or because your fuel system is weak. P0171 is a common trouble code in many vehicles.Ī “bank,” as in “bank 1,” refers to the side of the engine where each of your car’s cylinders is found.
“Code P0171 – system too lean bank 1” means there is too much oxygen or too little fuel in the exhaust, which is referred to as a “lean” condition, or a lean or “low fuel trim” code.
